The figure standing on the ramp provides a relative size comparison with the XB-70A aircraft. Six large nozzles for the General Electric engines are shown between and below the two large vertical tails.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. One was flown by the NASA Flight Research Center (now NASA Dryden), Edwards, California, in a high speed flight research program.