About 35,000 feet (10,670 meters) over the Mojave Desert, northwest of Los Angeles, Boom Supersonics XB-1 became the first privately funded airplane to break the sound barrier during a test flight on Tuesday.She was real happy supersonic, Boom Chief Test Pilot Tristan Geppetto Brandenburg said after landing, in a video posted by Boom Supersonic. Thats the best shes ever flown, was supersonic.After getting to altitude, Brandenburg opened up the test planes throttles, accelerating to Mach 1.1, or about 845 mph (1,360 kph) faster than the speed at which sound travels.In 1947, Chuck Yeager became the first human to break the sound barrier when he pushed the Bell X-1 past Mach 1 during a flight over the Mojave Desert.Boom Supersonics XB-1 is a stepping stone in its plan to develop a commercially viable supersonic airliner, the Overture, capable of carrying 64-80 passengers across the Atlantic in about 3 1/2 hours.The company has 130 orders and pre-orders from American Airlines, United Airlines and Japan Airlines.Last year, it completed construction on its Overture Superfactory in Greensboro, North Carolina, where it plans to build 66 Overture aircraft per year.Dan Catchpole, Reuters