The unmanned X-51A WaveRider, which is more of a missile than a plane, was launched off the coast near Port Magu and reached hypersonic speed (that's more than five times the speed of sound) before plunging into the ocean. At that speed, a passenger plane from L.A. to NY would take under an hour. But commercial applications are many decades off - even developing a plane that can fly at supersonic speed has been basically shelved by manufacturers and airlines because it would require too much fuel to operate and result in all sorts of environmental problems. Why do you think the Concorde never flew across the country? By the way, the X-51A was developed in Southern California by Boeing Co.'s research center in Huntington Beach and Pratt & Whitney Rocketdyne in Canoga Park. From the LAT:
Since the 1960s, the Air Force has been flirting with hypersonic technology, which can propel vehicles at speeds that cannot be achieved from traditional turbine-powered jet engines. But the technology has been exceedingly difficult to perfect. Previous attempts produced very limited results. In Wednesday's test flight, the X-51A took off from Edwards Air Force Base, slung under the wing of a B-52 bomber. At about 50,000 feet, it was released like a bomb and engaged a solid rocket booster that accelerated it to Mach 4.8 in about 26 seconds. After separating from the booster, the X-51A scramjet engine then lit and accelerated to Mach 5.1 at 60,000 feet.