Sir Richard Branson has announced plans to re-introduce supersonic transatlantic flights within six years after his space company entered into a partnership with US-based start up Boom. Boom founder, pilot and former Amazon executive Blake Scholl, yesterday unveiled a prototype aircraft which he claims will be able to fly between London and New York in 3.5 hours. XB-1, located in a hangar at Centennial Airport in Denver, is a one-third scale version of the full production model that Boom aims to have ready for passengers by 2020. Branson claims the flights will cost $5,000 (about £4,000) return, which is more affordable than a transatlantic crossing on Concorde before it was scrapped. “I have long been passionate about aerospace innovation and the development of high-speed commercial flights,” Branson said. “As an innovator in the space, Virgin Galactic’s decision to work with Boom was an easy one. We’re excited to have an option on Boom’s first 10 airframes. “Through Virgin Galactic’s manufacturing arm, the Spaceship Company, we will provide engineering and manufacturing services, along with flight test support and operations as part of our shared ambitions.” Denver-based Boom said the jets will each have only 45 to 50 seats and eventually they could also offer supersonic flights to Tokyo and Sydney. Several other companies, including Boeing and Lockheed Martin, are developing new supersonic jets, but Scholl said his plan was likely to be the first to come to fruition as it doesn’t require any new technology that would need to be approved by regulators. Scholl said test flights would begin in southern California, with plans to launch the first commercial departures in 2023. Tickets will be cheaper than on Concorde, he said, because of developments in technology and lighter materials. Meanwhile, start-up private jet operator Bliss is planning to launch transatlantic flights from Stansted in January. it says it will operate flights to New York La Guardia, leaving Stansted on Friday afternoon, using 10 to 14 seat aircraft. Tickets will cost about $12,000 each way.