$25 tickets, quieter airports,

or even shorter runways.

Companies have been betting on

battery-powered planes for this cleaner future.

But even though electric planes

have been around since the 1970s,

they haven't really taken off.

So, what's keeping them grounded?

In the late 1800s,

two French army officers experimented

with electricity to propel an airship,

but they ran into problems

when the battery just couldn't hold enough energy.

This would become a recurring problem

for the next 100 years.

When nickel-cadmium batteries were invented,

the first flight with an electric motor took off,

but it only lasted less than 15 minutes.

Then, in the 1980s,

lithium-ion batteries were invented.

They could store more power than ever before,

leading to planes like the Solar Impulse 2.

Starting in 2015, the solar-powered aircraft

spent 16 months flying around the world,

except it flew at an average speed

of 28 to 34 mph.

Solar Impulse 2 is part of a movement

in recent years to develop alternative energies,

especially when people and governments started realizing

just how bad flying was for the environment.

The aviation industry emitted

about 1 billion tons CO2 in 2019.

That's about 2.5% of global emissions.

That might not sound like a lot,

but it's almost as much as the entire continent

of South America emits in a year.

Kevin Noertker: We need to make changes to the industry,

and electrification is one of the big trends

which will hopefully reduce that burden.

Narrator: Electric planes have been

on people's mind for a while,

but two big problems are keeping electric grounded.

First, the technology's not quite ready.

When you're trying to get an electric plane off the ground,

you want a battery that packs a lot of punch

in a little package, but...

Carolina Anderson: Batteries are not as efficient as gas,

and they're probably not gonna be for a while.

Narrator: A battery's efficiency,

or ability to hold power,

is measured in specific energy.

Right now, even the best batteries have a specific energy

of only 250 watt-hours per kilogram,

but we have to get closer to 800 to really start flying,

and that is still nothing compared

to jet fuel's specific energy,

which is nearly 12,000 watt-hours per kilogram.

Think about it like those computers from the '80s.

They were huge, but way less powerful

than the sleek ones we have today.

Right now, batteries are like those '80s computers.

They're not as powerful as they need to be,

and they're not just big, they're also heavy.

So if you want to add more power to a plane,

you need to get a bigger battery,

and to get that plane airborne despite the weight,

you'll need even bigger battery that's more powerful,

but that means more weight.

And then you'll need an even bigger battery

to offset that weight.

Oh, you get the point.

But even if engineers design a plane

around the shortfalls in battery tech,

they have to take on the industry's second hurdle,

certification.

In the US, that means getting permission

from the Federal Aviation Administration

to test and fly an electric plane.

Companies have to prove every inch

of their aircraft is safe, passing a series of tests,

one of which is to make sure the battery cells

won't catch fire.

Roei Ganzarski: If something goes wrong,

you can't stop.

You can't pull to the side of the road.

There's only one place for that airplane to go.

And so the regulatory stringency is much higher,

the requirements for reliability,

redundancy, and safety

are much higher for a good reason.

You have no alternate.

Narrator: The FAA amended its rules in 2016

to allow electric propulsion systems in airplanes

built for up to 19 passengers.

The real problem, though, is that certification,

even with these amendments, takes years,

so companies have gotten creative.

They've started to retrofit old planes

to get certified quicker.

Ganzarski: You're taking out the entire old,

gas-guzzling, emission-creating engine

and its fuel system,

and replacing that space and weight

with an electric propulsion system.

Narrator: Retrofitting has happened in phases.

The first phase was from Slovenian company Pipistrel.

It created the world's first all-electric

two-seater plane back in 2007

by putting an electric engine in a glider.

Tine Tomažič: Gliders are safe to fly by definition,

even without a functioning engine,

so we were able to experiment

without putting anybody at risk

or do harm to anyone.

Narrator: Today, those planes are used for pilot training.

The second phase: a hybrid.

Los Angeles company Ampaire replaced one of the two engines

in a 1973 Cessna with an electric one.

Ampaire hopes to get its new plane, the Electric Eel,

certified for commercial flights by 2021.

And, finally, over in Vancouver,

electric-motor manufacturer MagniX

and Vancouver-based airline Harbour Air

flew a retrofitted 62-year-old plane.

A 15-minute test flight in December 2019

made it the world's first

all-electric commercial plane to fly.

It proved that electric could actually take off.

The two companies' goal is now to electrify

the rest of Harbour Air's fleet

of more than 40 seaplanes

and have it certified by the end of 2021.

So, retrofitting seems perfect.

The problem, though, is that it limits you

to what the plane structure is already built for,

so if the original motor is, say,

1,000 pounds, and you remove it, then...

Ganzarski: I only have 1,000 pounds to put back in, right?

I can't make the total package heavier.

Narrator: Electric motors are smaller

and lighter than gas ones,

but remember, those batteries are heavy.

Ganzarski: So you lose range because batteries,

for the same amount of power,

are so much heavier than fuel.

Narrator: So while Harbour Air and MagniX

figured out the balance of weight in their plane,

the range took a hit.

Their electric plane can go over 100 miles,

a little less than the distance from Seattle to Vancouver,

but for electric planes to be successful long-term,

they'll have to go farther.

Israeli company Eviation might have a solution.

Instead of retrofitting an old plane,

its engineers built a plane from scratch.

The nine-seater plane, Alice,

was designed around the battery to reduce weight.

Omer Bar-Yohay: That battery's literally all over the place.

It's under the floor, it's in the wings,

it's the fuselage in different locations.

Narrator: Alice, in theory, could fly up to 650 miles,

roughly a flight from Las Vegas to Denver,

but because it was built from the ground up,

getting her certified is taking longer.

Bar-Yohay: We're very confident that we will be

testing the plane in flight early 2020

and believe that from that point on

the certification process will take about two years.

Narrator: Each electric plane in development

is different, but they all have one thing in common:

they're going after flights under 500 miles.

And while it may not seem like an impressive distance,

these short-range electric planes

could solve a major problem in travel.

In 2018, a little less than half