Lockheed SR-71 Operations In The Far East - Even before the first operational flight of the U-2 spy plane, aircraft designers began work on the type's replacement. The result was the SR-71. First deployed on March 9, 1968, this tri-sonic 'hotrod' flew its first operational sortie over North Vietnam just 12 days later. Thereafter, it roamed freely, capturing photographic, radar and electronic intelligence. - Osprey Combat Aircraft Series