 It was only the advent of the Korean War in 1950 which slowed down the retirement of the B-29.Once again, the Superfortress was pressed into combat; while for the first six months the B-29 was able to hold its own, the introduction of jet fighters such as the MiG-15 ended its usefulness; the B-29 was too slow and its defenses were inadequate against fast-moving jets.By 1953, except for some RB-29s, they were withdrawn from combat.