The two companies are investing in Heart Aerospace, a company producing electric aircraft that has already developed a 19-seat passenger plane powered by electric engines. The two airlines have ordered 200 aircraft designed to operate with zero carbon emissions.

    On its aircraft, Heart uses batteries of the same type intended for electric vehicles. Air transport has been subject to increasing criticism as a major source of world-wide greenhouse gas emissions. 

    Analysts say narrow-bodied and regional aircraft are responsible for nearly half of emissions attributable to aviation. Several companies are developing electric-driven aircraft intended for short-haul flights.

     Heart’s 19-seat plane will have a greater range than its competitors – a range of up to 400 km using  lithium-ion batteries. The first such ES-19 aircraft for commercial use is due to be delivered in 2026.

    United Airlines plans to reduce its greenhouse gas emissions to zero by 2050. In order to pursue that aim., the airline is ordering 15 aircraft with zero carbon emissions from Boom Supersonic and is investing in the company Vertical Aerospace for the development of electric Vertical Take-off and Landing (VTOL) planes. 

    Aircraft in the |United States are now actively using biofuel mixed with traditional refined oil products.