A port side view, taken from close alongside the tail looking to starboard and forward, of the YF-4K2 (Phantom) prototype aircraft (serial XT 596) at the McDonnell Douglas aircraft factory at Saint Louis, Missouri. The completion to first flight status of the two prototype aircraft for the Royal Navy's Fleet Air Arm was the reason for a press viewing day at the factory. YF-4K1 (serial XT595) first flew 26 June 1966 and left the factory for the Edwards Air Force Base 21 July 1966. YF-4K2 (serial XT596) first flew 30 August 1966.