♪ ♪ MILES O'BRIEN: The race is on to stop the climate emergency.

BRICE NZEUKOU: We're seeing more and more people really paying attention to their carbon footprint.

♪ ♪ O'BRIEN: Aviation is a fast-growing offender, but is it too slow to respond?

SUSAN YING: Aviation will become the final dinosaur that doesn't clean up if we don't act right now.

O'BRIEN: It's the high-hanging fruit-- one the hardest climate challenges of all.

BERTRAND PICCARD: It's extremely difficult to get rid of the fuel, if you want to transport tons and tons of passengers.

♪ ♪ O'BRIEN: Could rapid progress in electric technology change the equation?

TERIK WEEKES: Electric motors are at a certain point today.

The battery systems are at a certain point today.

We're within that edge of possible.

O'BRIEN: New technology is driving a global race to push that edge.

SEBASTIAN THRUN: This might sound crazy, but we believe it's the future of transportation for everybody.

♪ ♪ O'BRIEN: A new era may be closer than you think.

Are we flying the future right now?

We absolutely are.

O'BRIEN: "The Great Electric Airplane Race" is cleared for take off-- right now on "NOVA."

♪ ♪ ♪ ♪ All right, Wendy, this your first day flying?

Actually, yep, this is my first flight.

O'BRIEN (voiceover): A trip to the airport in Watsonville, California, shrouded in mystery.

I've been invited here by a publicity-shy company... (engine starting) For a flight to an undisclosed location to see a groundbreaking new flying machine.

Beyond that, details are sketchy.

Our pilot is Wendy Kraft.

You've been flying helicopters for a long time.

Is this the kind of thing you'd like to share with many more people, that ability to go anywhere, anytime?

Oh, absolutely, especially in this area.

I mean, having grown up in Santa Cruz, there wasn't really a traffic problem back in the day, but now, traffic is horrendous.

O'BRIEN (voiceover): Helicopters are only for the lucky few.

It's about $1,000 an hour to operate this one.

And, of course, they're noisy.

(blades whirring loudly) We fly for an hour, and then...

Without warning, there it is, sitting on a remote airstrip-- a successor to the helicopter.

An aircraft that flies without a drop of fossil fuel, part of an electric revolution in flight.

One with the ambitious goal of democratizing the rare privilege we just enjoyed.

And maybe, just maybe, help save the planet.

♪ ♪ The climate emergency is here and now.

♪ ♪ The greenhouse gas carbon dioxide is at the highest level it's been in at least 800,000 years.

♪ ♪ It's an existential crisis that is prompting action.

Globally, about 15% of the human carbon footprint comes from transportation.

We see some signs of progress-- electric car sales are rising as prices drop.

We're seeing more and more people really paying attention to their carbon footprint.

O'BRIEN: But aviation?

It's one of the hardest transportation problems to solve.

(plane roars) Yet all over the world, engineers, entrepreneurs, and aviators are trying to meet the challenge.

NZEUKOU: We believe it's going to happen sooner than most people imagine.

If you fly on small commuter airlines today, you can expect some version of electric aircraft within the next five years.

O'BRIEN: Today it's hard to see, but it may just be a matter of time.

♪ ♪ Because electric motors are so small, yet powerful and responsive, designers can distribute them all over an aircraft and replace control surfaces like ailerons, stabilizers, and rudders.

The motors reduce drag and are much more efficient.

They are experimenting, starting small, creating some flying machines like never seen before.

♪ ♪ There's even more at stake than the climate emergency.

Aviation has a serious pollution problem that is just now coming into focus.

Just after dawn on a sunny, blustery October morning in Boston, a pair of scientists are chartering a fishing boat.

So we can definitely try to get to as close to the runway as possible.

O'BRIEN: But environmental engineers Neelakshi Hudda and John Durant of Tufts University... How much closer do you want to get, another hundred meters?

O'BRIEN: ...are casting...

This might be a good spot.

Might be a great spot.

O'BRIEN: ...for plumes of emissions generated by aircraft heading into Logan Airport.

Combustion of Jet A fuel in airplane engines is a bigger piece of the overall pollution pie than most people recognize.

The amount of Jet A that's consumed at Logan is about 25% of all the fuel that's consumed in the city of Boston by all the cars.

And there are millions of people that live around big, large airports that are impacted by these emissions day in and day out.

And it's a chronic insult, environmental insult, to those communities.

O'BRIEN: They are out to answer a simple question-- how pervasive is that chronic insult?

HUDDA: Basically, we are seeing a plume downwind from the plane, which results in a spike in the concentrations that we are measuring.

O'BRIEN: They are measuring the quantity and the size of toxic particles, the remnants of incomplete combustion.

HUDDA: Average size: ten nanometers, that's really small particles.

The smaller the particle is, the deeper it can penetrate into your lungs.

They have been associated with a slew of cardiovascular health effects, respiratory health effects, elevation in blood pressure, systemic inflammation, and have the capacity to actually penetrate the blood-brain barrier directly and deposit in human brain.

O'BRIEN: Hudda has an electric car outfitted with similar equipment.

HUDDA: So here's a size distribution... O'BRIEN: She drives through neighborhoods under the flight paths continuously gathering data.

(machinery humming) ♪ ♪ Her pioneering work began in Los Angeles in 2012.

Driving a similarly equipped car, she systematically traversed the neighborhoods beneath the final approach paths to Los Angeles International Airport.

She was able to identify a distinct plume from the airplanes that went much farther than she expected.

HUDDA: We went 20 kilometers, and I still don't think that's the end of it.

I just ran out of battery at that point in my car.

No one had suspected that they'd find a really clean signal 20 kilometers downwind of an airport.

If you look at the top 23 airports, about ten percent of the U.S. population lives within ten miles of those airports.

We all benefit from aviation, but we all don't really pay for it equally.

O'BRIEN: And yet we all pay a price for aviation's impact on the climate emergency.

Before the pandemic, aviation accounted for about three-and-a-half percent of the world's climate-warming problem.

About two thirds of jet fuel exhaust is CO2.

Less than one percent are nitrogen oxides, which also cause warming.

The other third is mostly water vapor, which at high altitude becomes ice crystals-- contrails.

When the humidity is right, contrails spread and linger for hours, creating cirrus clouds.

Thousands of flights creating thousands of contrail-induced clouds trap a lot of heat.

They have about twice the impact on global warming as the CO2 from jet exhaust.

And the problem is getting worse.

Global aviation is growing rapidly.

It is predicted to double in less than 20 years.

In stark contrast, other forms of transport are investing heavily in green alternatives.

YING: If that trend continues, then aviation is going to become one of the top polluters of all industry sectors.

Aviation will become the final dinosaur that doesn't clean up if we don't act right now.

O'BRIEN: It is a weighty issue.

Specifically, the weight of jet fuel.

A Boeing 737 can hold more than 40,000 pounds of it.

Sounds like a lot.

But to replace the jet engines with electric motors, you would need 30 times the weight, or about 1.2 million pounds of batteries to get comparable range.

♪ ♪ Solving that engineering challenge will be daunting, but the first baby steps have already been taken.

In 2003, Bertrand Piccard co-founded the Solar Impulse project in Switzerland.

The goal: to design and build a solar electric aircraft that could fly around the world.

PICCARD: For Solar Impulse, we had to make a very, very light airplane-- the weight of a car-- we're flying at the speed of a moped and transporting one pilot and zero passengers, and like this, we could fly solar with electric engines.

MAN (on radio): And we lift off... O'BRIEN: His partner in the audacious endeavor was Andre Borschberg.

BORSCHBERG: I had faith in the possibility to do it but of course I didn't know how.

Could we collect enough energy?

And could we use so little that it would make the flight through the night possible?

O'BRIEN: In the end, it took 16 months, but they did circumnavigate the planet.

(applause) We made it!

PICCARD: What I wanted to do was to show that electric aviation had also a future, and that the technologies already exist.

It's not something that we can do it in a hundred years.

We can do it now, and actually we did it.

Today, all the people who say, "Clean aviation is impossible," will look as stupid as the one who said to the Wright Brothers, "Your airplane will never fly."

O'BRIEN: Chandler Airport in Fresno, California, has been in operation since the Wright Brothers era-- Aviation 1.0.

Today the Art Deco glory has faded... but Joseph Oldham is using this old, underutilized place to help launch a new age of flight-- Aviation 3.0.

OLDHAM: This is the third revolution of aviation.

The first revolution, of course, was powered flight.

Second revolution was jets in the 1940s, early 1950s.

Electric propulsion is the third revolution.

O'BRIEN: These are Pipistrel Alpha Electros, the first certified, all-electric airplanes in the world.

He has four of them in his hangar.

And he was gracious enough to give a fellow pilot the right seat.

All right, we're in.

Contact, huh?

OLDHAM: Clear.

(propeller hums) Huh, that's amazing.

O'BRIEN (voiceover): It was as simple as flipping a switch.

That's it?

That's it.

O'BRIEN: It was weirdly quiet as we taxied to the runway.

OLDHAM: The noisiest thing on this airplane are the brakes.

O'BRIEN: And watch what happened when we stopped to wait for traffic.

OLDHAM: You just sit here, just like an electric car.

O'BRIEN (laughing): This just cracks me up.

Yeah, anytime anybody goes in this airplane that's used to a conventional aircraft, that's what gets them.

CALDWELL (on radio): Four Alpha Romeo, you can go ahead and roll.

OLDHAM (on radio): Four Alpha Romeo rolling.

♪ ♪ It's interesting, it doesn't vibrate in the same way.

OLDHAM: Yeah, it's just very comfortable and very relaxing.

Electric propulsion systems are so simple that really there's just nothing that you really need to be that concerned about.

Are we flying the future right now?

We absolutely are.

O'BRIEN (voiceover): It was a hazy day, the result of some raging wildfires nearby, a reminder of the climate emergency which makes the decarbonization of aviation so urgent.

How important do you think that is to think about taking fossil fuels out of aviation over the long run?

Well, it's huge, it's the only mode of transportation that really has not moved aggressively towards zero emission.

O'BRIEN: He got the money to purchase the planes by applying for a grant from Fresno County to demonstrate advanced transportation technology.

He believes the planes, along with charging stations at airports within range, will do just that.

OLDHAM: Well, we're heading into land right now so... You mind if I take it for a minute?

No, go ahead.

All right, good, thanks.

All right, let's do it.

Keep the ball centered.

Yep.

OLDHAM: There you go.

O'BRIEN: Ah, it's so smooth.

(voiceover): The range and endurance are still pretty limited by the batteries, so I didn't get much stick time, but it felt like a magic carpet.

OLDHAM: Electric propulsion opens up new opportunities for use of almost 5,000 general-purpose airports in the United States that are mostly underutilized.

Nice work.

Thank you.

♪ ♪ O'BRIEN: The company that makes this airplane is based in Slovenia.

Pipistrel is a pioneer of electric aviation.

Founder Ivo Boscarol started tinkering with ultralight trikes in the 1980s.

He designed these electric planes to be flight trainers for new pilots.

And Joseph Oldham also has that on his mind as well.

He is waiting for FAA approval to start a flight school with these planes.

And he thinks reduced maintenance and no fuel costs create an opportunity to bring more diversity into aviation.

While we spoke, instructor Chris Caldwell was giving student pilot Michael Murphy a lesson in a conventional piston-powered airplane.

Take that nose down just a little bit.

There you go, doesn't take much.

Yeah.

CALDWELL: Hey, you wanna try a no-flap landing?

Yeah, let's do a no-flap landing.

Okay.

Let's see how different that is.

Yeah.

♪ ♪ (plane engine roaring) O'BRIEN (laughing): They are having fun.

They're having too much fun.

That wasn't bad at all.

That was good, man.

O'BRIEN: Mike is a mentee of Joseph Oldham's.

He aims to fly for the airlines one day.

He hopes to be part of the first generation of pilots to begin their training in state-of-the-art electric airplanes, not 50-year-old relics that burn leaded gasoline.

Do you think electric airplanes are going to be a game changer for making aviation accessible to a broader spectrum of people?

Definitely, definitely.

Well, you're paying 200 bucks, you know, an hour to fly one of these little old 1960 airplanes, you know what I mean?

So, definitely, I think it does open up more doors for people to get their foot into aviation, at least, just kind of start off, you know, by flying these little airplanes.

What we're looking at is solving a pilot shortage and then also opening the door for more people of color, more people from different backgrounds, ethnicities, nationalities, and that's an international issue.

O'BRIEN: Two seats and only an hour of flight before the battery runs out, the Alpha Electro is a case in point of the infancy of all-electric aviation.

It is a long way from this... to that, a long-haul jet airliner.

♪ ♪ The flight path between the two may be wending its way through this small hangar in Camarillo, California.

Here, a small start-up company called Ampaire has modified a 1974 Cessna 337 Skymaster.

A twin engine-- one pushes, one pulls.

They replaced the forward piston engine with an electric motor and added a 600 pound battery pack to the belly.

It's a hybrid they call the EEL.

♪ ♪ I think we really need to focus on dialing in the propulsion system first.

O'BRIEN: Brice Nzeukou is the director of business and product development.

We strongly believe in a fully electric future, but we're waiting for regulations to develop, for technology to develop, as well, before we will see full electrification.

Hybrid is the way to enter the market.

O'BRIEN: They have flown dozens of test flights.

The electric motor does most of its work on take off and the climb to altitude.

And then the piston engine takes the brunt for cruise and descent.

Fuel costs are reduced by 20 to 30 percent, maintenance bills cut in half.

NZEUKOU: We are trying to bring this technology to market as quickly as possible.

And so we felt that going the retrofit route and starting with hybrid, as well, versus fully electric, provided a great mix of performance, cost savings, and our ability to get it done technically in a timely manner.

O'BRIEN: Not long after this flight test, they took the EEL to Hawaii.

♪ ♪ The company partnered with Mokulele Airlines to see how it handles commuter airline operations with frequent flights and short turnarounds between them.

NZEUKOU: That would be really tough to do in a fully electric plane because you would have to plug in and charge.

That's why this hybrid approach for us really made sense.

O'BRIEN: Ampaire is hoping the next step will look like this, a converted 19-seat twin Otter, with electric motors that run on batteries charged by an on-board turbine engine.

♪ ♪ Welcome to my hangar.

O'BRIEN: Susan Ying is Ampaire's senior VP of global partnerships.

YING: These regional airplanes buy Turboprop, or even jets, they're not making the profit.

In some of the regional market airlines, they're going out of business because they have very thin margin.

Electric aviation is going to change that.

O'BRIEN: The idea of jump-starting electrified aviation with hybrids, just as the Prius did for fully electric cars, is gaining traction in other places.

Like the Dogpatch, the San Francisco neighborhood that was once home of some shipyards, is now filled with young innovators thinking big.

And there it is.

O'BRIEN: But in this case, not too big, or so Kofi Asante hopes.

ASANTE: And what would you imagine the time before overhaul is going to look like?

O'BRIEN: He's head of strategy and business development for a small start-up called Elroy Air.

They are focused on an unpiloted vehicle that can carry 300 pounds of payload for 300 miles at 140 miles per hour.

ASANTE: If it's at one warehouse and needs to be at another warehouse, but it can't get there in time, you can all of a sudden enable same-day delivery in a way that wasn't previously possible.

♪ ♪ O'BRIEN: Batteries alone would not do the job.

The range would be limited to 30, maybe 50, miles.

So it also has an internal combustion engine.

Terik Weekes is Elroy's chief engineer.

WEEKES: In order to get something to market, one, we need to focus on an unmanned vehicle and then, two, focus on the hybrid electric vehicle.

This technology allows us to have a more efficient aircraft and have something that's more economically viable.

Hopefully these vehicles will eventually become all-electric, but we just don't know when.

O'BRIEN: They have hover tested this model, and now are designing the next iteration.

They believe it can help in the wake of natural disasters, or wherever there are obstacles to getting urgent items where they are needed, like vaccines.

ASANTE: Never before has rapid delivery, especially of urgent, like, medical supplies, or e-commerce, been this important.

It's just shot through the roof exponentially overnight.

Our goal is to try and be a part of that solution to help us get in a better spot.

O'BRIEN: But Elroy is thinking beyond delivery drones to another mission, which began with another Elroy.

SINGERS: ♪ His boy, Elroy!

♪ O'BRIEN: Yes, that Elroy.

The company was, and still is, dreaming of the Jetsons' flying car.

ASANTE: We believe that there will be a time where people are likely in flying cars and flying taxis.

It's hard to tell whether that's going be now or at what point in time in the future.

♪ ♪ O'BRIEN: Imagine a world filled with flying cars.

Electric propulsion might deliver the freedom of flight to our doorsteps.

♪ ♪ O'BRIEN: In China, one start-up is testing the waters, on drones big enough... to fly people, mostly on sightseeing tours of no more than ten minutes.

It is the EHang 216-- two passengers, 16 propellers.

O'BRIEN: It's not the first flight for this passenger.

Edward Xu is chief strategy officer of EHang.

XU: It's very smooth, just like an elevator.

You don't have to be a pilot.

You just are simply sitting as a passenger and this aircraft will take you to your destination.

O'BRIEN: The company claims it can carry 485 pounds up to 80 miles per hour, for about 20 miles.

Not nearly enough capability to change the face of personal transportation, but it has proven people are willing to try it, even without a pilot.

The company claims more than 6,000 have flown so far.

XU: Our company is a very innovative company.

We are doing something to change the world.

We are doing something that nobody has done before.

O'BRIEN: But they have a lot of competition.

EHang is among at least 200 start-ups across the globe, racing to fill the skies with electric vehicles.

For decades, aerospace has, for the most part, stayed relatively similar.

And now, you're starting to see a lot of groups starting companies, whether it be for smaller drones, or larger cargo drones, or flying taxis or cars.

There's been all sorts of movement there.

O'BRIEN: Before the pandemic, I met with aeronautical engineer Mark Moore, who sparked a lot of this creative thinking.

In 2009, then with NASA, he designed a concept vehicle called the Puffin.

MOORE: It was a single-person electric vertical take-off and landing aircraft that really opened the door to everyone's eyes of what electric vertical take-off and landing aircraft could be.

And so we actually called the Puffin the Gridlock Commuter, and that name just instantly clicked.

O'BRIEN: One of the people fascinated by Puffin?

Google co-founder Larry Page.

Soon after he saw it, he began investing in personal electric aircraft projects.

♪ ♪ At a ranch south of Silicon Valley, a small team from one of those companies, Kitty Hawk, is flight testing a single-seat electric aircraft called Heaviside.

The company is led by entrepreneur and computer scientist Sebastian Thrun.

He invited us for a rare peek and a slick pitch.

THRUN: This might sound crazy, but we believe it's the future of transportation for everybody.

THRUN: If you put the car in the air, there's no obstacle, you go in a straight line, you're not in anyone's way.

You don't need roads anymore, you're more energy efficient.

You're faster, you're safer.

Why would people not want that?

O'BRIEN: It's an electric vertical take-off and landing vehicle, or eVTOL.

The propellers pivot the thrust from horizontal to vertical, allowing the craft to take off and land on a dime... And still fly 180 miles per hour.

♪ ♪ MAN: Enabled.

Here we go.

O'BRIEN: The Kitty Hawk team is flight testing, aiming to be certified for piloted flight by the Federal Aviation Administration.

Tilting.

THRUN: We've built over a hundred fully functioning prototypes in the last years.

We've done almost 30,000 individual flights, and we've learned a lot.

We had, of course, incidents from which we learn.

Luckily, no one was ever hurt, we have always been safe.

But yeah, it's been an evolution to make sure that even the weakest part of the aircraft is strong.

O'BRIEN: Thrun believes the way to reconcile his big dream of a Heaviside in every driveway, with safety, is automation.

THRUN: People without a full piloting skill set and certification should be able to hop into those, punch in their target address and get there.

Before that, there's many steps we have to cross, but I see no technical reason why we couldn't accomplish this with this aircraft.

The reason why we do electric is we are just super quiet, like we fly over you and you can't hear us.

O'BRIEN: Sebastian Thrun is a pioneer in the development of autonomous cars.

He is the founder of Google's self-driving car project.

He says self-flying aircraft are an easier challenge.

THRUN: All the stuff to hit from your bicyclist, to your playing child, to your curb, to your shrub, they're all on the ground.

You go up 500 feet and there's nothing to hit.

And as we go through this, we've made it safer and safer and safer, in part by adding more and more redundancy.

O'BRIEN: But wait, no pilot?

Automation might be safer, but I'm not sure I'm ready to take the likes of Wendy Kraft out of this picture.

Which brings me back to my mysterious helicopter ride, to get a glimpse of its 21st century successor.

Maybe we should step over and see how it is to sit in the aircraft... O'BRIEN: JoeBen Bevirt founded Joby Aviation in 2009.

The aircraft he and his team designed is now in flight testing for FAA certification.

It's the current leader in the race to fill the world with electric air taxis.

BEVIRT: This aircraft is the culmination of a decade of research and development into how to build an incredibly safe, quiet, and cost-effective aircraft.

O'BRIEN: It carries a pilot and four passengers under six tilting motors.

BEVIRT: It provides us an aircraft which is incredibly good at hovering and incredibly good at cruising.

That efficiency and cruise is what gets us our range and gets us our speed.

O'BRIEN: He says it can fly 200 miles per hour and has a range of 150 miles.

BEVIRT: There are four batteries in the aircraft.

The batteries that we have in this aircraft right now are the batteries that we're going to production with and they provide us the range and performance that we need to fundamentally transform transportation.

O'BRIEN: Joby designs, tests, and builds almost all the components of its aircraft, giving new meaning to the term vertical integration.

BEVIRT: We developed the battery packs, we developed the propulsion systems, we developed the actuators, we developed the inceptors-- everything that you see here is something that is being developed and manufactured in-house.

O'BRIEN: Much of the work was done in secret in a barn on a secluded property among the redwoods in Santa Cruz.

BEVIRT: I wanted a place to be able to experiment and try crazy things.

O'BRIEN: There's an old quarry here where they did a lot of early flight testing.

These days, it is home to a circular track where they test motors for endurance.

BEVIRT: There were a number of years where we went through a huge amount of iteration and trial and error to learn about what were the best aircraft configurations.

MAN: Start confirmed.

We're at idle.

I'm gonna bring it to 200 rpm.

BEVIRT: Electric propulsion opens up a huge amount of design freedom.

It allows you to think really differently about how you apply the propulsion to the aircraft.

31 knots, 33 knots.

BEVIRT: The aircraft that you've seen is the culmination of many years of exploration.

♪ ♪ O'BRIEN: Back at the airstrip, I met chief test pilot Justin Paines, who spent years in the Royal Air Force flying Harrier vertical take-off and landing jets.

So, how much easier is this to fly, relative to a Harrier, or for that matter, a helicopter?

Chalk and cheese.

I could put you in it, I could stand behind you, and we could go flying and you'd be quite capable of flying the airplane, it's that simple to fly.

O'BRIEN: The goal is to have the aircraft initially certified for flight with a pilot.

The aircraft has flown hundreds of times, mostly by remote control.

Obviously you're still learning, but is it flying the way you imagined it?

Yes, this aircraft is flying incredibly well, it's a dream come true, and we're really excited to put it into production and share it with the world.

♪ ♪ O'BRIEN: Still media wary, JoeBen Bevirt allowed us to watch, but would not let us film one of their test flights.

I was impressed.

It is remarkably quiet, much quieter than a helicopter.

But the video the company shot and shared with us later has no audio, so the only public recording of its noise signature is captured in this promo, announcing Joby is now publicly traded by merging with a special purpose acquisition company.

Thank you so much.

♪ ♪ O'BRIEN: On paper, Joby was worth $6.6 billion when it went public.

The company hopes to have the aircraft certified in 2023.

BEVIRT: We want to be comparable in cost to the price of a taxi at launch, and bring that cost down to the cost of personal car ownership over the coming years.

O'BRIEN: Uber spent millions developing air taxi concepts, but in the midst of the pandemic, sold its notional flight division to Joby.

No one can accuse JoeBen Bevirt of thinking small.

BEVIRT: In order to have the impact that we want to have in order to transform the way everyone moves every day, we will need to make millions of these.

Our mission is to save a billion people an hour a day.

♪ ♪ O'BRIEN: A billion people flying air taxis?

How could that be safe?

At NASA's Ames Research Center in Silicon Valley, they're tackling the air traffic control challenge.

That's what led me here, to the legendary Vertical Motion Simulator.

Once upon a time, space shuttle astronauts honed their landing skills here.

There's nothing like it anywhere else.

Back on glide slope... O'BRIEN: And now, NASA is using it to understand how to devise a safe air traffic control system for advanced air mobility.

Hey, Gordon, how are you?

HARDY: Hey, great, Miles.

Let's go eVTOL flying, shall we?

Good to see you, yeah, hop in.

O'BRIEN (voiceover): Before the pandemic, veteran NASA test pilot Gordon Hardy gave me a glimpse of the future.

NICK: All right, computer's ready.

Cockpit's ready.

Operate.

O'BRIEN: So we're over San Francisco on a nice sunny day.

So I'm trying to imagine this city with hundreds of these aircraft buzzing around it.

HARDY (chuckles): Yeah.

What's that going to be like?

Yeah, yeah.

(chuckles) And hopefully not hitting each other, nor falling out of the sky.

O'BRIEN: Exactly.

(voiceover): But the world that Gordon is helping NASA create is designed to work without pilots like him.

Eventually, autonomous air taxis will need to safely fly to and from convenient places, taking off, navigating, landing, and dealing with emergencies, all on their own.

It's a complex problem.

BRIAN: So we should see it bank soon... O'BRIEN: In another building not far away, engineers are immersed in a 360 degree virtual depiction of the city, watching us fly.

BRIAN: We're tracking the UAM 003 currently.

That's the vertical motion simulator.

All right, looks good.

And the speed is okay?

O'BRIEN: Sandy Lozito is chief of the aviation systems division.

LOZITO: We have to think about all of those vehicles being in the air space at the same time, different performance parameters, potentially different training for the ones that are piloted.

And then how do we make sure that everything stays safe?

O'BRIEN: In this world, the idea of a control tower is outdated.

LOZITO: Looks like we've got the VMS going up and over the bridge.

Yeah, that's working perfectly.

All right.

O'BRIEN: Before COVID, there were more than 45,000 flights every day in the U.S.

It's an intricate symphony precisely conducted by air traffic controllers.

Are you good?

O'BRIEN: But if eVTOLs take off, there will be a lot more players.

LOZITO: We do not necessarily expect a centralized air traffic control tower to do it with individual directives telling the pilots how to come in and out of the vertiport.

And so, that's a very different operation.

There could be much more independence on the part of the pilots and the individual operators as they move in and out of these areas.

O'BRIEN: Independence?

It sounds like a prescription for disaster.

♪ ♪ But NASA has been working on this for the past few years, on smaller drones that don't carry people.

The lessons learned writing those rules are offering them a foundation.

SHARMA: So these would be its operations, right?

Coming in around here and landing here on top of this.

O'BRIEN: Shivanjli Sharma is an aerospace research engineer at Ames.

She and her team are using data from the simulations to write the algorithms that will allow air traffic control to be digital, more automated, and distributed.

The goal would be to share information with other operators and folks like the FAA to make sure that everybody in the airspace knows where one another really is flying.

O'BRIEN: In flight, an air taxi would continuously transmit its location to receivers on the ground.

SHARMA: As that vehicle is flying, we're monitoring its position in relation to that four-dimensional volume.

Are they inside that volume, are they outside of that volume?

Are they in that volume at the time they predicted they would be?

O'BRIEN: There are many hurdles.

At low altitudes in cities, GPS and cellular signals can be unreliable.

And what about security?

Transmitting all this mission-critical, life and death information across shared cloud networks offers its own set of risks.

And there's one other big challenge, this new air traffic control scheme needs to work safely alongside the old one.

LOZITO: If there are tubes in the sky or particular lanes of airspace in which these vehicles may transport, we know that at some point they're going to be near conventional aircraft, commercial aircraft, and we have to make sure that those can work together or can complement one another.

♪ ♪ O'BRIEN: Flying cars may seem distant to most of us, but for NASA engineer Starr Ginn, it's close to home.

One of the thought leaders on electric aviation, she lives in a house with a hangar, right beside a runway.

GINN: I feel so lucky, right, I get to live in a Sky Park and can get in my airplane and go wherever I want.

This whole time in my mind, I've been thinking, "I want everybody to be able to have what I have."

O'BRIEN: On this Sunday morning, she and her husband Tony, also a NASA engineer, decided to air out their Thorp T-18.

♪ ♪ A speedy little homebuilt airplane.

♪ ♪ How low can you go?

There's two hundred, 2-0-3.

Can you go lower?

♪ ♪ STARR: Whoo-hoo!

(laughs) TONY: Too much fun.

That's the best feeling.

Yeah.

O'BRIEN: Fast as the Thorp is, she knows it could do better.

The wing is not optimized for speed, deliberately.

Typically, a general aviation airplane's wing's designed for stall, low-speed performance.

O'BRIEN: The faster air moves over a wing, the more lift it provides.

And the greater the surface area of a wing, the more lift it can create.

So for safety's sake, wings are made wide enough to provide adequate lift at slow speeds.

But once an airplane levels off and starts flying faster, the added lift from that fat wing is no longer needed.

In fact it's a drag-- literally.

The extra surface area makes the airplane less efficient.

Making a wing narrower would reduce drag, but at slower airspeeds would not create enough lift.

Electric motors offer a solution to this dilemma.

They are so lightweight that they can be placed all across that narrow wing.

Even at slower speeds, the extra airflow from these motors adds lift.

In a way, they're tricking the wing into thinking it's flying faster.

GINN: You're blowing air over those wings as if they think they're up in the air just cruising in your normal speed of flight.

O'BRIEN: To test out the idea, she teamed up with fellow NASA engineer and Puffin creator, Mark Moore.

GINN: It was a very small contingency around the NASA aeronautics centers that were this different group of...

I don't know, rebels.

O'BRIEN: They attached 18 electric motors, made by Joby, to a slender wing and mounted it high above a truck to avoid interactions with the vehicle and the ground.

MOORE: It looked like a Mad Max truck with a big distributed electric propulsion wing that we drove across the desert because we couldn't afford a wind tunnel.

GINN: It wasn't any, you know, spectacular kind of thing, but it got us the information we wanted.

At the same time, Mark and I were getting ready for a pitch to say, like, we should really, like, put this on an airplane.

They convinced NASA brass to create the first piloted experimental, or X, plane in more than 20 years.

It's the X-57 Maxwell.

It will have 14 Joby electric motors that will test the advantages of distributed electric propulsion.

MOORE: You're not dependent on a single motor or controller, but you distribute that power across the airframe so that if any one breaks, the vehicle can still fly.

O'BRIEN: Sean Clarke is now the engineer in charge of the program.

Putting 14 motors on an airplane is not obviously a good idea, but we want to take the time to find out, is it reasonable to build an aircraft around that configuration?

O'BRIEN: Maxwell is a modification of an existing piston engine aircraft.

The new wing is only 40 percent of the width of the slow speed wing it replaces, a huge reduction in drag.

It will take off with all 14 motors running.

Once leveled off, the 12 smaller motors will be shut down to conserve batteries, the props folded back.

It's a challenging conversion.

The wiring required for all those motors, their electronics, and the instrumentation has to fit in a very tight space.

And it's on the inside edge, too.

It's on the inside edge.

That's going to be a little bit tricky.

Yes, and then we're also concerned a little bit about the edge right where it comes out.

Oh, okay.

O'BRIEN: But the Maxwell team has faced even more daunting challenges than this.

In 2016, they ran a test on the lithium ion batteries.

They stressed them to see how safe they might be if they failed in flight.

CLARKE: What we found is when one cell fails, it makes the next cell over get really hot and it fails, and then the next one fails, and you have a chain reaction through all 5,000 cells on the airplane, potentially.

O'BRIEN: So they reached out to NASA experts who designed the batteries used by astronauts in space.

The collaboration led to a much safer battery pack for Maxwell.

They hope to fly it in 2021.

CLARKE: I'm really interested in these technologies finding their way onto passenger aircraft, to transport class aircraft someday, but we need to work up to that.

This is the next step up; we want to be able to put a pilot onboard and have our pilot understand and feel the response of the propulsion system and start working toward that transport class dream.

O'BRIEN: The transport class dream, carrying hundreds of passengers and tons of cargo, hinges on range, speed, and payload.

For now, batteries come up short on all fronts.

And while they are getting steadily better, about five percent a year, the gap is so wide it will take at least a decade for them to catch up, if ever.

Is there a way to decarbonize aviation sooner?

In Stuttgart, Germany, electrical engineer Josef Kallo is working with a company called H2Fly.

They're making airplanes that run on hydrogen.

KALLO: At the moment, the most promising technology emission-free is to have fuel cells with hydrogen.

O'BRIEN: Fuel cells generate electricity through an electrochemical reaction.

Hydrogen reacts with incoming oxygen to generate electricity.

That current powers electric motors.

The byproduct is water.

Hydrogen has three times more energy density than jet fuel and is the lightest molecule of all.

But at atmospheric temperature and pressure, it's a gas, so it takes up a lot of volume.

And the energy can't flow out of the cell as fast as it can from a fossil fuel engine or a battery, so there's less power available for takeoff.

But it offers much more range.

KALLO: With the technology, using a fuel cell with hydrogen, from today's perspective, we can say that we can go six times to eight times longer in range.

♪ ♪ O'BRIEN: Kallo and his team have been at it for 13 years.

This is his sixth generation aircraft.

It has batteries to provide enough power for takeoff.

In November of 2020, Kallo says they test flew it more than 30 times, validating a range of nearly 500 miles.

KALLO: This will prepare the way forward to have much, much longer-range hydrogen fuel cell, electric propulsion, and then in that step, we will have very efficient planes, a very efficient electric propulsion, and also a very long range.

So I would say, from an economic point of view, 80 to 100-seater with a range of 3,500 kilometer is feasible.

O'BRIEN: Almost half of all emissions from aviation come from flights of less than 2,000 kilometers, or 1,200 miles.

Hydrogen could make a big dent.

KALLO: We are definitely in a revolution in the aviation.

This is very exciting, very interesting times.

♪ ♪ O'BRIEN: They are times that demand action to address the climate emergency.

But this solution does not rely solely on altruism.

Electric aviation can rise on its own merits... because there is green in flying green.

NZEUKOU: Air travel will be more affordable, it will come from a ton more places.

Electric aviation opens up the number of airports that we can actually operate commercial service out of.

GINN: We know all the pieces that have to be put in place.

It's just, how long does it take to prove the reliability of that piece, and then prove each of those pieces' reliability in a system.

That takes time.

It's going to happen.

O'BRIEN: It's like Detroit in the early 1900s, inventors racing to define what the automobile would look like, a hothouse of innovation, that started and stayed in garages for years, and then seemed to change the world overnight.

Those competing in the great electric airplane race are convinced a revolutionary moment like that is in the air.

♪ ♪ Solar Impulse pioneer Andre Borschberg is still chasing the dream in Switzerland.

He has retrofitted a two-seat piston aircraft with an electric motor.

MAN: Runway 25 clear for takeoff.

BORSCHBERG: Okay, let's go for a nice circuit.

♪ ♪ O'BRIEN: The company he started is called H55.

BORSCHBERG: There is only one switch when you get into the cockpit here.

You know pilots, you like to be free.

Here you get free from the need to use the fuel tank.

All electric, no combustion, no CO2, no pollution.

When you fly electric, you don't want to go back to combustion engine.

It's so convincing that you say, "Now, I want to continue with this technology."

WEEKES: Electric motors are at a certain point today.

The battery systems are at a certain point today.

We're within that edge of possible where we think things will mature a lot quicker.

BORSCHBERG: You cannot do everything in one day.

But if we don't start today, we will not be ready in ten, 15 years to be totally clean.

ASANTE: It almost feels like there's some part of the future that we think about as, like, at some point in time, this is inevitable and now we're all just mapping out the plan to try and to get there.

BORSCHBERG: It's fantastic, eh?

No vibration, little noise... that's the future.

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