A prototype for a new jet that aims to transport passengers from New York City to London in 3 1/2 hours was unveiled in a hangar in Denver on Tuesday.

Richard Branson, founder or Virgin Group, is collaborating with Boom, a Denver-based startup, to build a new generation of supersonic jets. Branson said his private space exploration company, Virgin Galactic, and its manufacturing arm, The Spaceship Company, would help Boom to build the jets that will have flight times comparable to those offered by Concorde.  Flown by British Airways and Air France from 1976 to 2003, Concorde was used almost exclusively by very wealthy passengers because of high ticket prices.

Boom would succeed where Concorde failed because developments in technology and lighter materials would result in lower ticket prices, Branson said.

A 3 1/2-hour, one-way flight from New York City to London would cost $2,500. A flight from San Francisco to Tokyo would take 5 1/2 hours (instead of 11 hours currently) and cost $3,250 and a Los Angeles to Sydney flight would take 6 hours,  45 minutes (rather than 15 hours) and cost $3,500. The plane would travel at a speed of 1,451 miles per hour, which is 2.6 times faster than any other airliner.

Boom will have 45 to 50 seats, compared with Concorde’s 92 to 128.

Branson is partnering with Blake Scholl, founder and CEO of boom, as well as a pilot and former Amazon executive. Several other companies, including Boeing and Lockheed Martin, are also developing new supersonic jets, but Scholl says that Boom is likely to beat them to market because it does not require any new technology that would need approval by regulators.

Test flights are scheduled to begin in Southern California in 2017, and commercial departures are expected to be introduced in 2023.

Scholl said the plane could work on 500 different routes, but initially would focus on London to New York City, San Francisco to Tokyo and Los Angeles to Sydney.