American Airlines has announced an order for up to 20 supersonic aircraft from Boom Supersonic. The carrier also reserves the option to purchase 40 more supersonic jets, reports The Verge.

In two years, this is the second airline that bets on supersonic flights. If the Boom planes pass the test, the company plans to be able to deliver them in 2025. They should fly in 2026, and start carrying passengers by 2029.

Supersonic planes will help significantly reduce travel time. From New York to London, such a plane will reach in 3.5 hours instead of 7, and from Los Angeles to Sydney in 6 hours 45 minutes instead of 15 hours.

The contract with American Airlines is not the only promising one in Boom’s portfolio. The company also has an agreement to supply 15 aircraft to United Airlines and contracts with Rolls Royce and the US Air Force.

Last July Boom showed the updated design of their supersonic aircraft Overture. It will have a length of about 62 meters, climb to a cruising altitude of 18,300 meters and develop a speed of Mach 1.7.

The company also said the planes would be adapted to run on 100% sustainable aviation fuel and have “zero net carbon.” However, the details of how they plan to achieve this have not yet been revealed.