Designed originally to destroy enemy aircraft in aerial combat, the F-100 later became a fighter-bomber. It made its combat debut during the Vietnam conflict where it was assigned the task of attacking such targets as bridges, river barges, road junctions, and cantonment areas. The F-100 had originally been designed as an air superiority fighter, but the "A" model was the only pure air superiority version. The "B" model was an all weather fighter. As the Air Force began to realize the F-84 fighter-bomber fleets were showing signs of age, the logical choice was to modify the F-100. Thus was born the F-100C. The F-100C which made its first flight in 1955, featured such advances as an in-flight refueling system, provisions for extra fuel drop tanks and bombs under the wings and an improved electronic bombing system. The "D" model was the definitive version with 1,274 examples eventually produced. It had improvements in both aerodynamics and weapons delivery, capable of carrying nuclear weapons.