If you’ve ever played with a carbon footprint calculator(opens in a new tab) and plugged in your flight history, you’ve seen how a trip just an hour or two away ballooned your total impact on the environment.

All that jet fuel takes a toll, but electric planes may swoop in and help — one day. Instead of those 176 pounds of carbon emissions for one measly roundtrip flight from San Francisco to Los Angeles, an emissions-free aircraft could fly that same distance. 

Tesla — and to a lesser extent Nissan, Chevy, and even Toyota with its hybrid Prius — made the masses believe in electric cars. Now, many companies want flyers to believe in electric planes. 

Aviation startups are working to remove expensive, polluting jet fuel from the flight equation and replace it with electric batteries. The idea of electric planes isn’t new, but we're closer than we've ever been thanks to battery improvements.

“A long tail of activities that happened in the past decade have led to this little explosion in electrification,” Kevin Noertker, CEO and co-founder of electric aviation startup Ampaire, said.

Electric flight was first tested in the 1800s and the innovations kept coming through the second half of the 20th century(opens in a new tab). French military engineers Charles Renard and Arthur Constantin Krebs added batteries and an electric motor to an 1880s aircraft, according to Air and Space Magazine(opens in a new tab). Then in the 1970s, experimenting with electric and solar power got a jump start. The past 15 years have seen a huge number of notable electric flights take off, lasting 20 minutes to several days. The experimenting continues today, but more so with passenger flights.

This new wave of research and development comes as jet fuel prices have skyrocketed(opens in a new tab), and U.S. and foreign regulators have put out calls to reduce emissions(opens in a new tab). Globally, nearly 5 percent of emissions(opens in a new tab) come from from flying. The International Civil Aviation Organization, or ICAO, an agency within the United Nations, wants to be carbon neutral by 2020(opens in a new tab), but to get to that goal something has to change.

Everyone wants to be the first to take off.

Hotspots for electric flight innovation have popped up in Washington state, the Los Angeles area, Israel, Germany, and other parts of eastern Europe.

And while the startups are eager to put their concepts into practice, we’re only just starting to see the first iterations of these planes. Instead of only two people on a 300-mile flight, like the June 2011 e-Genius flight out of Germany, the electric plane industry wants to one day match what we consider everyday commercial flights. Back in 2011 that flight path was hailed as the longest distance flown by an electric aircraft carrying people.

Companies like Los Angeles-area startups Ampaire and Wright Electric are working on planes for regional travel. Ampaire founders imagine six- and 19-passenger electric planes, while Wright Electric representatives dream of a fuel-free 150-seater plane(opens in a new tab). 

Wright Electric’s Jeffrey Engler is modeling his aircraft after the passenger planes you’re used to taking from the airport. His company wants to hit the sweet spot for electric travel — about a distance of 300 miles or less.

By the end of this year, Ampaire wants to retrofit a six-passenger plane into an electric and hybrid craft, called TailWind. It has designs for new aircraft as well — like its 19-passenger plane concept. Ampaire’s Noertker, a mechanical engineer who came from traditional aerospace company Northrop Grumman, sees aviation electrification as an extension of what’s happening with electric cars and other vehicles on the ground.

If these sound like small planes, it’s because they are. Compared to the planes that industry giants like Boeing and Airbus develop, Ampaire and its competitors are building puny aircraft. But it’s a big achievement to get a handful of people several hundred miles on an electric charge.

Wright Electric entered the scene in 2016. The next year, the Massachusetts-turned-Los Angeles -based company was at the tech incubator event Y Combinator Demo Day and debuted its high-flying goal to build an all-electric passenger plane(opens in a new tab) that would make short-haul flights within the next 10 to 20 years.

The recent explosion in electric flight comes with a fairly lengthy list of startups in an industry that doesn’t usually have a startup culture. Unlike the endless upstarts offering a new smartphone app or biotechnology innovation, the aircraft manufacturing business is mostly dominated by the establishment.

“It seems all players in the ecosystem are still finding their footing,” Noertker said, referring to the new guard.

The newbies include Eviation, an Israeli firm that expects its models with propellers on the wingtips to take off in 2019, Germany’s Lilium, with its electric vertical take-off and landing taxi jet for five people, and Zunum Aero, a hybrid plane company in Washington state preparing to test flights in 2019.

Just because there’s competition to be first doesn’t mean the companies aren’t helping each other.

“It’s pretty collaborative at this point,” Noertker said. The small companies have to work together to a certain extent. There isn’t a fully established supply chain yet and “we don’t compete on safety,” Noertker explained.

“It’s much more collaborative than it is competitive,” Eviation CEO Omer Bar-Yohay echoed. “We have a battery, you have a battery.”

So best practices, information, and solutions get passed around. Getting a new airplane certified is a big challenge, so if working together can get everyone closer to that goal, they will. Others skirt around U.S. Federal Aviation Administration, or FAA, hold-ups with experimental testing, which involves a far less rigorous permitting process.

“There is an aspect of pressure to move as fast as possible,” Noertker noted, with a few companies claiming they’ll be flying something by summer 2019.

“I hope none of the companies take this pressure to fly early and make bad decisions based on it,” he added. As seen with the fatal Uber crash in Arizona(opens in a new tab) earlier this year, a tragedy like that can be a setback for the entire industry.

To get these aircraft flying, all the companies are working with batteries, electric motors, wings, and some even with propellers.

Electric planes use batteries to power an electric motor instead of jet fuel to power an engine. They need a motor that can turn electric power into mechanical energy — and they need a battery.

Eviation’s Bar-Yohay compares electric planes to its traditional fuel-powered equivalent. Instead of building a plane around a gas-guzzling engine and huge engine-cooling radiators, electric planes need to design around a battery.

Since batteries don’t have the energy density of fuel, Eviation’s plane has a “very, very big battery” weighing in at 3.8 metric tons. That’s 60 percent of the plane’s total 14,000-pound weight. A traditional plane devotes 30 percent of its total weight for fuel.

Electric batteries use the charge to power an electric motor to spin when magnetic forces pull on a rotor. As an example, the NASA video below shows a lithium-ion battery powering a propeller.

“Electric motors are very good at short bursts of power,” Wright’s CEO Engler explained.

Another benefit: reduced maintenance, especially since electric motors don’t need gearboxes to slow down the engine. And “the fuel cost is not only reduced but gone,” said Roei Ganzarski, CEO of MagniX, which is developing motors for electric planes in Redmond, Washington.

Jet engines turn at very high RPMs, wearing down equipment quicker. Traditional jet engines(opens in a new tab) work when air is sucked through and blades spin and compress the air that is then mixed with fuel. The air and fuel mixture is sparked and expands and blasts out of the engine through the turbine, powering the plane(opens in a new tab). 

Electric is also quieter and cleaner, opening up possibilities to fly different routes and times out of reach for traditional airplanes because of noise restrictions in residential and urban areas.

Electric planes. Flying cars. EVTOLs. Passenger drones. Flying pods. Flying taxis. Hybrid-electrics. These are not just different ways to describe an electric plane. Each one is its own thing, sometimes featuring only subtle differences.

Smaller contraptions certainly advance the playing field, but the taxi-like aircraft UberAir(opens in a new tab) is proposing for long-distance commuting is in a whole other ball game than a 737 jet taking 150 passengers from San Francisco to LAX while running on electric power.

Air New Zealand plans to use Kitty Hawk’s Cora autonomous electric taxi(opens in a new tab) planes for shorter trips throughout New Zealand, although the airline hasn't set a launch date yet. The Cora planes were introduced in March.

Usually the smaller flying contraptions and electric vertical, take-off, and landing vehicles (the eVTOLs), or passenger drones, are intended to fly a few people at a time. In Dubai, a self-driving two-seater eVTOL was taking test runs last year.(opens in a new tab)

“As much we don’t like to admit it, aviation is a risky business,” MagniX CEO Ganzarski said. So his company, which is electrifying planes for cargo, not people, can fly planes with boxes and packages in the back and serve as “the perfect canary” for 100-mile range trips.

Ganzarski aims to fly a converted electric Cessna 208 Caravan by fall 2019. “The engine doesn’t care if it’s boxes or people” on board, Ganzarski said.

To add to the convoluted list of electric aircraft, there are also helicopters, like the SureFly octocopter drone(opens in a new tab), a small helicopter expected to arrive in the next two years. 

Then there are hybrid planes, which use a combination of electric and gas power. It’s like the Toyota Prius, but it’s up in the air. Zunum Aero is working with Safran Helicopter Engines for its 12-seater hybrid aircraft that is expected to fly in the early 2020s.

It’s not just a matter of swapping out an internal combustion engine and setting off into the sunset.

Samuel Engel, senior vice president at consulting firm ICF’s aviation group(opens in a new tab), considers the concept of electric passenger planes operating like the daily afternoon Southwest flight from Atlanta to Las Vegas as “experimental.”

“We’re more likely to teleport in my lifetime than see large-scale commercial electric aircraft,” he said.

But that doesn’t mean we won’t see electric planes up in the sky — he acknowledges the determined startups will make something work. But within the aviation industry, he sees too many obstacles for full deployment. 

“Aviation is a fundamentally conservative industry,” he said. “We don’t like to take risks because we don’t like planes to fall out of the sky.”

First some basic engineering challenges need to be conquered, or somewhat mitigated. Weight is a big problem, Engel pointed out. Jet fuel’s energy density, or how much energy you can get out of a substance, is about 50 times that of batteries — even if electric propulsion is more efficient at turning energy into motion. Liquid fuel burns off, so as you fly, planes actually get lighter. That doesn’t happen with batteries as they lose charge. Instead, you’re carrying dead weight that needs to be recharged — and that’s another can of worms.

To add to the obstacles, Engel mentioned limited power and charging sources, lagging airport infrastructure, and regulatory hurdles. The FAA took decades to accept composite structures(opens in a new tab) in airplanes, like the fully-composite Boeing 787 Dreamliner that arrived in 2009 or the geared turbofan engine(opens in a new tab).

“That cycle is so slow,” he said, referring to deploying new technology on a commercial scale.

Then there are the batteries.

Ampaire’s Noertker sees promise with high-energy density battery cells that would store enough energy on board so you can fly a meaningful distance. Think of Tesla’s Powerwall, a solar battery pack, but without the sun and without the Tesla. Modern motors can provide a lot of power with little weight — essentially improving efficiency, Noertker said.

Charging these batteries is another matter. A 500-kilowatt battery requires a lot of power. 

"It’s basically turning on a Costco just to get a charge," Eviation’s Bar-Yohay said. His company envisions charging trucks that come to the planes at airport landing strips to charge up the crafts, essentially creating mobile battery-to-battery charging stations.

Engel, the skeptic analyst, is more optimistic that hybrid electric planes will take off sooner than their all-electric cousins.

The various startups each have their own ambitious goals for takeoff. Ampaire is targeting the end of this year to get its six-seater up, while Wright is looking into the next two decades to build out a much larger aircraft.

Eviation has set 2019 as a take-off date to start testing fully electric flights and 2022 as when regular customers can buy a ticket for an all-electric regional commuter flight. Lilium says its first “fully functional” jet is forecast to take off in 2019 as well. By 2025, Lilium customers are expected to be booking on-demand electric taxi planes. Uber’s electric taxi eVTOL is supposed to start demoing in Dallas and Los Angeles by 2020 and be commercially available by 2023.

Looking at this more realistically, a true electric passenger flight taking a plane-full of passengers from New York to London is 20 years off. And that’s being generous. As MagniX’s Ganzarski said, “so much needs to happen” to get to that point.

If these flights work out, they could be a game-changer, especially for the environment. Until then, it’s time to work on your carbon footprint here on the ground. Your gas-guzzling car might not emit as much as that plane trip, but it’s still a lot.