The U2 first flew in 1956 as a high altitude recconnessaince aircraft. It could fly at 80,000ft which was well above what Soviet fighters could reach and it was thought they couldn't track an aircraft at this height. This proved not to be the case when a U2 was shot down at 70,000ft by a Soviet SA-2 missile in May 1960. The Pilot survived and was later returned to the US. The U2 remains in service today.
