XB-70 Valkyrie supersonic aircraft. This is the first version of this 1960s US supersonic aircraft, the XB-70A (62-0001). Here, it is taking off in the morning to take advantage of the cooler conditions. The wing tips are extended straight out to provide maximum lift. Capable of flying at three times the speed of sound, this was the world's largest experimental aircraft at the time. The flights took place between 1964 and 1969. Two XB-70 aircraft were built by North American Aviation, one used by NASA for a high-speed flight research program. It was 57 metres long, with a wingspan of 32 metres. Photographed on 17 August 1965.