An "Alice" electric aircraft manufactured by Eviation Aircraft sits on display during the 53rd International Paris Air Show at Le Bourget, in Paris on June 18, 2019.

Tucked away among the more conventional passenger and military planes on display at the Paris Air Show sits a little nine-passenger aircraft offering a glimpse into the future.

The all-electric prototype developed by Israeli venture capital-backed Eviation Aircraft Ltd. was shipped to the biennial exhibit in pieces because it's never been flown before. Yet the battery-powered aircraft called the Alice snagged its first customer, Cape Air, and is aiming for commercial flights in about three years.

The plane has drawn out-sized interest because the aviation industry is increasingly under pressure about carbon emissions from burning kerosene. Air travel is on track to become the single biggest emitter of carbon dioxide within three decades if forecast cuts in other sectors materialize, according to data and projections from UN agencies. While energy generation and agriculture dwarf aviation's approximately 2% share of all human-caused greenhouse gases, output from air travel is accelerating many times faster.

"We don't have a solution and it's a really hard problem," said Paul Eremenko, chief technology officer at United Technologies Corp., owner of jet engine maker Pratt & Whitney. "We're going to have to innovate our way out."

He was speaking on possible remedies at a press conference with executives from plane manufacturers Airbus, Boeing and Dassault Aviation as well as engine makers Rolls-Royce Holdings, General Electric and Safran. The companies on Tuesday agreed to cooperate in a number of areas.

They called for development of aircraft and engines that are more fuel efficient and emit less carbon dioxide. They also backed use and wider availability of alternative aviation fuels and the development of "third-generation" aviation that would include electric and hybrid engines and new materials.

Even before the Paris show, the warning lights were on for the industry. Augustin de Romanet, head of airport operator Aeroports de Paris, said the sector is becoming the "scapegoat" of the transport industry when it comes to emissions. Already in markets like Scandinavia, the concept of flight-shaming is gaining traction, to prevent people from using aircraft excessively and get them to switch to alternative modes of transport. Yet unlike the car industry, which has long had to abide by rules on exhaust, aviation has been exempt from binding measures.

The International Civil Aviation Organization recently moved to address the omission of airlines from the 2015 Paris climate accord by adopting self-policing guidelines known as Corsia for offsetting any carbon increases by planting trees or investing in cleaner technologies. The measure is a "stop gap" to try to stabilize emissions, according to Michael Gill, head of the Air Transport Action Group, an industry lobby.

The International Air Transport Association, the industry's biggest trade group, has targets to cap net carbon emissions from 2020 and halve them by 50% by 2050 relative to 2005. While executives at the Paris Air Show spoke of a "moral imperative" to achieve them, industry growth raises the challenge.

Airplane pollution, which has risen by about two-thirds since 2005, is forecast to jump as much as sevenfold by 2050 as incomes in developing economies advance, making flying more affordable for hundreds of millions if not billions of people, according to the Montreal-based ICAO. IATA expects the number of airline passengers to double by 2037, to more than 8 billion a year.

The surge in demand is swelling the global fleet of commercial passenger craft, which Boeing sees doubling to 40,000 in the same period. The pool of private jets is increasing at a similar pace, with JetCraft, a market-intelligence firm, predicting a 50% gain within a decade, to 30,000 from 20,000. That's without adding cargo and military craft to the mix.

There's no simple solution because alternative fuels aren't widely available at a competitive cost to replace kerosene and development of hybrid and all-electric engine technology is ongoing and is still years away for large jetliners. Not surprisingly, the industry is against a push by some European countries to tax kerosene.

"There's an urgent need for alternative fuels," said Greg Hyslop, chief technology officer at Boeing, who pointed to successful biofuel flights on a 777 model. "The technology is there, now we need to work the economic side to make sure enough is available."

On another front, the timetable for developing new engines could see small hybrid-electric planes ferrying 10 to 20 passengers by the middle of the next decade and as many as 40 in bigger regional-sized aircraft by about 2030, according to Stephane Cueille, chief technology officer at Safran.

"The pressure coming from the outside is good news, it puts pressure on the industry to get better, faster," Airbus Chief Executive Officer Guillaume Faury said in an interview. "Hybrid is the first way of going electric before we go full electric on the long term — and starting on the short distances."

Consultant Roland Berger reckons there are 100 different electric-aircraft programs in development worldwide, up 30% since 2017, and that the technology could help constrain aviation's carbon dioxide emissions to 2% to 3%.

After the Paris Air Show, Eviation Chief Executive Officer Omer Bar-Yohay said he's going to ship the company's electric plane to Arizona to get ready for a first flight planned for later this year and certification in 2021.

"This isn't some future 'maybe one day' project," he said in an interview. "It's here, now and being built."

