 The MiG patrols and attacks in North Vietnam were taken over by the F-4s and F-105s based in Thailand, which could carry a larger bomb load further and faster.In addition, the F-105 was built to take the extreme structural loads of low-level, high-speed flight, whereas the F-100 was not.Consequently, the F-100D fighter bombers generally operated only in South Vietnam where the F-100 turned out to be a very effective ground support aircraft, and beat back many enemy attacks.