French start-up Aura Aero announced Tuesday that US regional airline JSX has signed a letter of intent to purchase 50 of its hybrid-electric planes. The deal, which includes an option for a further 100 aircraft, takes to nearly 500 the number of the 19-seater Electric Regional Aircraft (ERA). The aircraft, which sports eight propellors and can take off on battery power, aims to deliver an 80-percent reduction in CO2 emissions from current regional aircraft. The aircraft is currently in development. The first flight is planned for 2026 and entry into service in 2028. JSX is a Texas-based firm that offers premium service from private terminals using small regional jets. Aviation is one of the most difficult industries to decarbonise, with the development of sustainable aviation fuel the leading method being looked at by researchers.