North American AT-6 Texan
The Texan was built as both an inexpensive export fighter as well as a trainer, and several of them have seen combat in various countries you would probably have to look up on a map. It also trained a lot of pilots, and was the master of disguises: while the Air Force called it the AT-6, the Navy knew it as the SNJ and RAF referred to it as the Harvard. Some Texans even went on to a successful movie career after the war, impersonating Japanese Zeroes.
Cool stuff for T-6 lovers: