Clifford "Cliff" Secord (aka The Rocketeer) is the main protagonist of the Rocketeer comic book and movie. He is played by Billy Campbell.
During the Pre WW2 he found a rocket pack hidden inside an old plane in hangar 3 which was stolen from Howard Huges who created this flying contrapion by gangsters who work for the sinister Neville Sinclair the actor who turns out to be a Nazi spy.