pacopico writes: A startup out of Denver called Boom Technology has just come out of stealth mode [by] talking-up their supersonic jet. It would carry 40 passengers and travel at Mach 2.2. The company claims that it's about 30 percent more fuel-efficient than the Concorde. Based on this, it could get its prices down to the equivalent of a business class seat on long-haul flights. At Mach 2.2, a trip from New York to London would take 3.4 hours. Boom is meant to start test flights next year out of John Denver's old hangar.