Development work began in 1949 for a supersonic interceptor and prototype construction started in 1951 when the company won a contract for 110 aircraft. The first YF-100 prototype flew on May 25, 1953 with a Pratt & Whitney J57 engine, it broke the sound-barrier on its first flight. The YF-100 set a world speed record in October 1953 at 754.99 mph. The first aircraft, the F-100A, were delivered in late 1953 and became operational from September 1954. Despite the testing, there were a number of operational crashes that grounded the aircraft from November 1954 until February 1955 when the problem (stability) was identified and solved (larger control surfaces).
The F-100A was followed by the F-100C (1954, 476 built) and the F-100D (1956, 1,274 built) fighter-bombers, with increased wing-area, fin and rudder size, six underwing hard-points and improved electronics. The F-100D was an unforgiving aircraft, over 500 were lost in accidents by USAF pilots. The final production variant was the F-100F tandem trainer (339 built), first flown in 1956 it was stretched by 3 m to accommodate the second crew.