In this view the #1 XB-70A (62-0001) is in a level cruise flight mode at a relative high altitude judging from the darkness of the sky. The XB-70A, capable of flying three times the speed of sound, was the world's largest experimental aircraft in the 1960s. Two XB-70A aircraft were built. Ship #1 was flown by the NASA Flight Research Center (now NASA Dryden), Edwards, California, in a high speed research program.