United Airlines aims to bring back supersonic travel before the decade is over with a plane that is currently just an artist's drawing - even the prototype hasn't flown yet.
The airline said Thursday that it plans to buy 15 jets from Boom Supersonic with an option for 35 more once the start-up company designs a plane that flies faster than the speed of sound while meeting safety and environmental standards.
United hopes to carry passengers on the plane in 2029. The airline said the plane will reduce flights between London and the New York area to just 3 1/2 hours and make Tokyo only six hours from San Francisco.
United declined to discuss financial terms, but Boom CEO Blake Scholl said the deal was worth $US3 billion, or $US200 million per plane with none of the discounting that is typical in the aircraft business.
It has been nearly two decades since the last flight of the supersonic Concorde, which British Airways and Air France began using in 1976 to zip passengers in luxury across the Atlantic. The last one was retired in 2003, three years after an Air France Concorde crashed into a hotel shortly after takeoff from Paris, killing everyone on board and four people on the ground.
Several companies are working to come up with new supersonic jets that would be more economical on fuel - and create fewer climate-changing emissions - than the Concorde.
Boom is working to develop an 88-seat plane it calls Overture, which it says will be the first supersonic airliner to fly on so-called sustainable fuel. Scholl said that a one-third sized prototype will make its first test flight later this year or early in 2022.
The Denver company said the plane will be capable of speeds up to 1.7 times the speed of sound, or about 2,092 kilometres per hour. That is slower than the Concorde but more than twice as fast as many current airliners.
The endorsement from United is a huge lift for Boom. Another supersonic contender, Aerion, said last month that it was running short of money to get its plane, the AS2, into production.
Supersonic jets are often banned over populated areas because of the sonic booms they create. That eliminates many potential overland routes because the planes would have to fly at less efficient subsonic speeds.
Chicago-based United believes that its coastal hubs in San Francisco and Newark, New Jersey, and its corporate-traveler clientele make it better suited than its rivals to offer supersonic service.
Mike Leskinen, United's vice president of corporate development and a former aerospace analyst, said United hopes to offer both premium and economy seating but that no final decisions have been made on cabin layout.
United is sensitive about the high fares that helped doom the Concorde, and is trusting that the cost to operate the Boom plane will come down over time as it has for other jets.
The Concorde was the pride of British and French aircraft companies, and it ushered in a new era of rapid travel over long distances. The plane had a distinctive delta-wing design that made it easily recognisable as it streaked overhead on its way to New York or Dulles Airport outside Washington.
Despite its cachet, the plane never caught on widely. The sonic booms limited its routes over land, and its high costs and relatively small size compared with other jets made tickets too expensive for anyone other than the wealthy or well-connected.
Henry Harteveldt, a travel analyst for Atmosphere Research, said the Boom jet appears targeted at business flyers, but corporations are trying to cut travel spending and might resist putting employees on supersonic flights if the fares are too high.
Scholl said the Boom jet will be 75 per cent cheaper to operate than the Concorde thanks to decades of advancements in engines and lighter fuselages.
"This is going to be a ticket that's affordable to way more people than supersonic ever has been before," Scholl said. He predicted that the speed of supersonic flight will revolutionise air travel the way that jets replaced most large propeller-driven planes.
Not everyone who follows aviation is convinced, noting that developing a new plane costs many billions of dollars.
Richard Aboulafia, an aerospace analyst at Teal Group, said he believes that if there were a profitable market for supersonic airliners, Boeing and Airbus would be building them.
"It tells you that the enormous, established players don't see it," he said. "There is no reason they couldn't do this. There is no secret sauce that Boom keeps in a safe somewhere."