An American airline company is planning to reintroduce supersonic flights by 2029.

According to an article via BBC News, United Airlines is purchasing 15 new supersonic airliners manufactured by Boom – a start-up company based in Denver, Colorado.

The aircraft to be produced, named Overture, is said to be expected to achieve a top speed of 1,122 mph (1,805 km/h), despite Boom not having tested the jet in the air. This is approximately twice the speed that a standard passenger jet would cruise at, however this would be slightly slower than the speeds reached by Concorde which was retired in November 2003.

One of the key features of the Overture aircraft is said to be its ability to run on 100% sustainable aviation fuel.

“Faster travel is an urgent human need, which is why we’re building the world’s fastest airliner — and doing so in a sustainable way,” said Blake Scholl in a statement, who is the CEO of Boom.

“We are designing Overture so people can travel more often — without worrying about environmental impacts. Throughout Overture’s lifecycle — from maximizing fuel efficiency in aircraft design to accommodating 100% sustainable aviation fuels to facilitating aircraft recycling — we are ensuring that Overture achieves the highest levels of sustainability.”