United Airlines announced in September an order for 200 of Eve Air Mobility’s eVTOL aircraft.The carrier put down $15 million for Eve, which follows the $10 million deposit it made for another eVTOL in August.United has invested heavily in electric and supersonic planes as it prepares its future fleet.LoadingSomething is loading.United Airlines is taking a big gamble on futuristic planes.The Chicago-based carrier announced a $15 million investment for 200 of Eve Air Mobility’s electric take-off and landing (eVTOL) aircraft earlier in September. Eve is a subsidiary of Brazilian planemaker Embraer. EVTOLs are urban air mobility vehicles that are designed to be low or zero-emission transport options in populated areas. They are ideal for short hops from city centers to airports to avoid congested roadway traffic. According to the carrier, United is the only major airline to invest in two eVTOL companies. The airline put down $10 million in mid-August for eVTOLs being developed by California-based Archer Aviation. United, in partnership with regional carrier Mesa Airlines, ordered 200 of the flying taxis in February 2021.The two investments brings United’s total orders for eVTOLs to 400.The commitment is part of United’s corporate venture that is “designed to support the company’s 100% green commitment to reach net zero emissions by 2050 without the use of traditional offsets.”The Air Transport Action Group (ATAG) announced the industry-wide commitment in October 2021, which the International Civil Aviation Organization (ICAO) also welcomed, though United independently made the ambitious pledge in December 2020.The carrier has since made several moves towards that goal, like flying a passenger jet with 100% sustainable aviation fuel (SAF) and helping produce hydrogen-electric engines. United has also ordered Boom’s supersonic Overture jet that is expected to run on 100% SAF. American Airlines has also purchased the ultra-fast plane.Nevertheless, one of the most popular decarbonization solutions continues to be electric aircraft, with United saying it has “confidence in the urban air mobility market.”Carriers like Virgin Atlantic Airways and American Airlines have also ordered eVTOLs, such as Vertical Aerospace’s VX4, while Tokyo-based All Nippon Airways has partnered with Joby Aviation to bring a five-seater eVTOL to Japan, but none have placed bets on two manufacturers.Atlanta-based Delta Air Lines has not invested in any electric aircraft or supersonic plane, however, with CEO Ed Bastian telling Fox Business that he “has a lot more questions than answers still” when it comes to Boom.While eVTOLs are becoming popular, there are some hurdles the industry must face, like establishing robust infrastructure to accommodate the operation and outlining regulatory standards that uphold safety.Despite the challenges, United is going all in on eco-friendly aircraft, with 515 currently on order. Here are the aircraft that the company is expected to start flying as soon as 2024.Archer AviationArcher Aviation Midnight.Archer AviationArcher Aviation is a California-based company developing two eVTOLs, including the four-seater “Midnight” and the two-seater “Maker” aircraft. United’s February 2021 order is worth $1 billion, and the carrier put down a $10 million deposit in mid-August for “Midnight.”According to Archer, the four-seater flying taxi can fly up to 60 miles at speeds of up to 150 miles per hour. The eVTOL is scheduled to be in service by 2024.Heart AerospaceUnited Airlines and Heart Aerospace partner to develop an electric aircraft.United AirlinesSwedish startup Heart Aerospace is developing a 19-seater electric plane called ES-19. While not an eVTOL, the aircraft will run on batteries and electric motors instead of jet fuel and carry passengers up to 250 miles. United ordered 100 ES-19s in July 2021 and expects the plane to be flying in 2026. Mesa also ordered 100 of Heart Aerospace’s electric plane, while Air Canada has ordered 30 ES-30s, which is the 30-seater version of the aircraft.Boom SupersonicBoom SupersonicSince the demise of the famous Concorde supersonic jet in 2003, there has not been another ultra-fast plane in commercial aviation. However, Colorado-based newcomer Boom Supersonic hopes to get its $200 million Overture aircraft flying by 2029.United announced its purchase for 15 Overture jets in June 2021 in a deal worth $3 billion. The jet will fly at Mach 1.7 and fly up to 80 passengers in an all-business configuration.Eve Air MobilityUnited AirlinesEmbraer’s Eve is one of the most popular flying taxis, having signed letters of intent with operators like Florida’s Global Crossing Airlines and regional carrier Republic Airways.United’s 200-strong order brings the four-seater eVTOLs’ backlog to over 2,000. The flying taxi will travel up to 60 miles, reduce noise by as much as 90%, and be flying by 2026.