The B52 Stratofortres was introduced in 1955 qty 744 The B-58 Hustler was introduced in 1960. (not to replace B52). qty 116 The FB-111A / F-111G was introduced in 1968 * qty 76 The B-1 Lancer was introduced in 1986 to replace the B-52. qty 104 The B-2 Spirit was introduced in 1997 to replace the B-52. qty 21 The B-21 Raider to be introduced in 2025 to place the B1 and B52. qty 6 +??
* The FB-111A was a strategic bomber version of the F-111 for the USAF Strategic Air Command. With Air Force's Advanced Manned Strategic Aircraft program proceeding slowly, and concerns of fatigue failures in the B-52 fleet, the service needed an interim bomber quickly