United Airlines has announced a deal to buy 1,300mph supersonic airliners in a move it said 'represents a leap forward in returning supersonic speeds to aviation'.

United said it would purchase 15 'Overture' aircraft from Denver-based aerospace company Boom Supersonic to add to its global fleet, with an option for an additional 35 aircraft.

Overture is slated to roll out in 2025, fly in 2026 and expected to carry passengers by 2029. Concorde, the last supersonic passenger jet, entered service in 1976 and continued flying for 27 years.

Capable of flying at speeds of Mach 1.7 – twice the speed of today's fastest airliners – Overture, said United, 'can connect more than 500 destinations in nearly half the time'.

It continued: 'Among the many future potential routes for United are Newark to London in just three and a half hours, Newark to Frankfurt in four hours and San Francisco to Tokyo in just six hours. 

'Overture will also be designed with features such as in-seat entertainment screens, ample personal space, and contactless technology.'

United added that Overture, which will be able to fly at 60,000ft, is expected to be the first large commercial aircraft to be net-zero carbon from day one, optimized to run on 100 per cent sustainable aviation fuel (SAF).

'The world's first purchase agreement for net-zero carbon supersonic aircraft marks a significant step toward our mission to create a more accessible world,' said Blake Scholl, Boom Supersonic founder and CEO.

'United and Boom share a common purpose - to unite the world safely and sustainably. 

'At speeds twice as fast, United passengers will experience all the advantages of life lived in person, from deeper, more productive business relationships to longer, more relaxing vacations to far-off destinations.'

United CEO Scott Kirby said: 'United continues on its trajectory to build a more innovative, sustainable airline, and today's advancements in technology are making it more viable for that to include supersonic planes. 

'Boom's vision for the future of commercial aviation, combined with the industry's most robust route network in the world, will give business and leisure travelers access to a stellar flight experience. Our mission has always been about connecting people and now, working with Boom, we'll be able to do that on an even greater scale.'

Last year, Boom unveiled a full-scale supersonic jet prototype, the first of its kind to take flight in nearly 50 years.

Earlier this year, meanwhile, rival supersonic jet firm Aerion unveiled a 'first glimpse' of its AS3TM airliner, designed to transport up to 50 passengers at up to 'Mach 4+' - or at least 3,000mph.

Florida-based Aerion said that conceptualization and design work for the jet was underway, 'built around input from potential customers'. Before the AS3TM takes to the skies, Aerion plans to launch its 1,000mph AS2 business jet.

And in March this year, new eye-opening renderings were released of the interior of a 1,100mph (Mach 1.6) supersonic jet by Boston-based Spike Aerospace that's slated to begin test flights in 2022 and begin flying passengers in 2028.

Concorde remains one of only two supersonic transports to have been operated commercially.

It had a maximum speed of twice the speed of sound at Mach 2.04 (1,354mph or 2,180kph at cruise altitude) and could seat 92 to 128 passengers.

Concorde was jointly developed and manufactured by Aérospatiale and the British Aircraft Corporation (BAC) under an Anglo-French treaty.

Air France and British Airways each received seven aircraft.

Concorde was retired in 2003 due to a general downturn in the commercial aviation industry after the type's only crash in 2000, the September 11 attacks in 2001, and a decision by Airbus, the successor to Aérospatiale and BAC, to discontinue maintenance support.