United Airlines Ventures (UAV) has signed a conditional agreement to acquire 100 ES-19 aircraft from electric aircraft start-up Heart Aerospace.

The purchase follows Heart Aerospace’s $35m Series A funding round, which was led by UAV, Breakthrough Energy Ventures (BEV), and Mesa Airlines.

Mesa Airlines is the key strategic partner of United in delivering electric aircraft into commercial service.

The 19-seat electric aircraft will contribute to United Airlines’ commitment to reducing  100% of its greenhouse gas emissions by 2050.

The aircraft could be deployed to operate on more than 100 of United’s regional routes once operational.

Currently under development by Heart Aerospace, the ES-19 is designed to fly up to 250 miles.

The aircraft will leverage electric motors instead of jet engines and batteries instead of jet fuel.

Heart Aerospace plans to deliver the first aircraft for commercial use by 2026.

United Corp development and investor relations vice-president and UAV president Michael Leskinen said: “Breakthrough Energy Ventures is the leading voice of investors who are supporting clean-energy technology creation.

“We share their view that we have to build companies who have real potential to change how industries operate and, in our case, that means investing in companies like Heart Aerospace who are developing a viable electric airliner.

“We recognise that customers want even more ownership of their own carbon emissions footprint. We’re proud to partner with Mesa Air Group to bring electric aircraft to our customers earlier than any other US airliner.

“Mesa’s long-serving CEO, Jonathan Ornstein, has shown visionary leadership in the field of electric-powered flight.”

Late last month, United Airlines ordered a total of 270 aircraft worth more than $30bn at list prices from Airbus and Boeing.