It’s not your daddy’s Concorde. A fleet of engineers at Colorado-based startup Boom is working on a new generation of passenger planes that break the sound barrier and fly much faster than the standard 615 mph. Learning from Air France’s expensive transatlantic failure, they’ve reduced noise and increased fuel efficiency. The price barrier remains, however, with one-way tickets for three-hour flights between New York and London estimated at $5,000. With plans to launch early next decade, Boom hopes technology costs will drop enough to make supersonic travel affordable for everyone.