The T-33 Was The World's First Jet Trainer. The Lockheed T-33a, Developed From The F-80 Aircraft, Served With More Than 30 Air Forces As A Trainer And Was Still In Use In 1979, More Than 30 Years After Its First Flight. The Lockheed F-80 Shooting Star Was The First Jet To Enter Service With The US Army Air Force. During The Korean War, It Engaged In What Was Among The First Combat Battles Between Opposing Jet Fighters.