McDonnell Douglas YF4H-1 Phantom II single-seat first prototype 142259 first flown in 1958

On 25 July 1955, the Navy ordered two XF4H-1 test aircraft and five YF4H-1 pre-production examples. The Phantom made its maiden flight on 27 May 1958 with Robert C. Little at the controls. A hydraulic problem precluded the retraction of the landing gear, but subsequent flights went more smoothly. Early testing resulted in redesign of the air intakes, including the distinctive addition of 12,500 holes to "bleed off" the slow-moving boundary layer air from the surface of each intake ramp. Series production aircraft also featured splitter plates to divert the boundary layer away from the engine intakes. The aircraft was soon in competition with the XF8U-3 Crusader III. Due to cockpit workload, the Navy wanted a two-seat aircraft and on 17 December 1958 the F4H was declared the winner.