Lockheed YF-12A 60-6936 with white cross on belly 2 Published on April 29, 2013 in 1 May 1965Full resolution (1800 × 1426) ← Previous Next → Lockheed YF-12A 60-6936 during speed record trials. The white cross on the aircraft’s belly was to assist timers and observers. (U.S. Air Force)