United Airlines has become the largest airline to invest in hydro-electric aviation with a new equity stake in hydrogen-electric engine developer ZeroAvia.

Under the agreement, United will pursue a conditional purchase agreement for 50 ZeroAvia ZA2000-RJ engines, with an option for 50 more, enough for up to 50 twin-engine aircraft which would be operated by United Express partners once they are fully developed and certified by regulators as soon as 2028.

The airline described the investment as its latest move towards achieving its goal of reducing its greenhouse gas emissions by 100 per cent by 2050, without relying on carbon offsetting.

“Hydrogen-electric engines are one of the most promising paths to zero-emission air travel for smaller aircraft, and this investment will keep United out in front on this important emerging technology,” said United’s CEO Scott Kirby.

“United continues to look for opportunities to not only advance our own sustainability initiatives but also identify and help technologies and solutions that the entire industry can adopt.”

The ZA2000-RJ is expected to be used in pairs as a new power source for existing regional aircraft.

“This support by United, alongside our other forward-thinking partners, demonstrates the importance of hydrogen-electric propulsion in the future of sustainable flight,” said ZeroAvia’s founder and CEO Val Miftakhov.

“The United Express routes powered by hydrogen-electric aircraft will be enabling large numbers of passengers to take zero-emission flights well within this decade.”