SINGAPORE (Reuters) - Electric airplane start-up Eviation Aircraft Ltd is aiming for its 9-seat commuter aircraft to be flying passengers by 2021 after signing up South Korea’s Kokam as its battery supplier, the Israeli company’s chief executive said on Thursday.

Venture capital-backed Eviation is one of a number of companies looking to develop small electric aircraft that would incur lower energy and operating costs, release less emissions and be quieter than their conventionally fueled counterparts.

Airbus SE AIR.PA, Boeing Co BA.N and Uber Technologies Inc are also investigating electric and hybrid aircraft technology.

Eviation CEO Omer Bar-Yohay said his firm signed a deal with Kokam last week because, as a smaller supplier, Kokam was able to make batteries more specific to his company’s needs.

“If I would go today to Samsung or Panasonic or LG Chem or Tesla for that matter and say I need a different cell size, they will probably laugh because the number of cells we are going to buy is not significant enough to start the design process,” he told Reuters in a phone interview.

The battery will have 9,400 cells distributed throughout the aircraft including the ceiling, floor and wings, weighing 3.8 tonnes, or 60 percent of the maximum takeoff weight.

Electric airplanes are reliant on improvements in battery technology, which is why smaller aircraft are likely to be electrified years before large commercial jets.

Batteries are heavy and store far less energy per kilogram than jet fuel, but the ratio is improving gradually each year, allowing electric cars and airplanes longer ranges than they had previously.

Eviation’s “Alice” airplane is expected to have a range of up to 650 nautical miles (1200 kilometers), compared to 1000 nautical miles for a similar-sized conventional Cessna Caravan. It will cost $2 million-plus, on par with the Cessna, but have far lower fuel and maintenance costs, Bar-Yohay said.

Eviation hopes to fly the Alice demonstrator for the first time by the end of the year, with the first public display at the Paris Airshow in mid-2019, he said. Moving to commercial production after that would require raising around $100 million of capital.

Given the advantages of going electric, major manufacturers are also investing in electric and hybrid aircraft technology.

Seattle-area startup Zunum Aero, backed by the venture capital arms of Boeing and JetBlue Airways Corp JBLU.O, announced plans in October to bring a 12-seat hybrid-electric commuter aircraft to market by 2022.

Airbus is working on the CityAirbus concept, a four-passenger electric aircraft capable of vertical takeoffs and landings, with the first demonstrator flight expected later this year. Ride-hailing firm Uber is exploring a similar concept with Uber Elevate.