Captain Boggs of the American Air Force is a brave and skillful pilot who is reduced to desk duty, which frustrates him, as the rest of the guys are out fighting the Japanese and disdain him for staying behind and being safe.
Boggs gets into a P-51 Mustang which he owns and goes out to wage a private war on the Japanese and various costume criminals, and then, after the war, on Communists and UFOs.