Cliff Secord (aka The Rocketeer) is the main protagonist of the Rocketeer comic book and movie. He is played by Billy Campbell.
During the 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.
In 1938 Los Angeles, California, two members of mobster Eddie Valentine's gang steal a rocket pack from Howard Hughes. During their exciting escape, they find themselves in an airfield, where the hide the rocket, but end up in an accident while escaping the airfield. Stunt pilot Cliff Secord, whose plane was damaged in the accident, and airplane mechanic Peevy find the mysterious rocket inside a bi-plane in their employer's hangar, where the getaway driver hid it. Meanwhile, famous actor Neville Sinclair who hired Valentine's gang to steal the rocket, sends his monstrous henchman, Lothar, to the hospital, where the injured getaway driver tells him that he hid the rocket at the airfield. Sinclair dispatches the mobsters to search for the missing device.
Cliff's aspiring actress girlfriend, Jenny Blake, is on the set of a Neville Sinclair film. Cliff arrives. Sinclair overhears Cliff attempting to tell Jenny about the rocket pack and invites her to dinner at a popular night club. Shortly afterward, at an air show, Cliff uses the rocket (with Peevy's newly designed face-hiding helmet, which also acts as a rudder) to heroically rescue his elderly friend Malcolm, who is drunkenly piloting a malfunctioning bi-plane. Having been seen by the audience, The Rocketeer becomes a media sensation.
Sinclair sends Lothar to retrieve the rocket; the search leads to Cliff and Peevy's residence. The FBI arrives, but Cliff and Peevy escape with the rocket. While escaping, Lothar steals detailed schematics drawn up by Peevy. At the local diner, Cliff and Peevy, trapped by a team of mobsters, learn that Jenny had a date with Sinclair and of the latter's involvement in the hunt for the rocket pack. The diner patrons overpower the mobsters; but a ricochet punctures the rocket pack's fuel tank, which Peevy provisionally patches with Cliff's chewing gum.
At Sinclair's villa, Jenny discovers that he is a Nazi secret agent and knocks him out. Sinclair recaptures her and leaves a message for Cliff to bring the rocket pack to the Griffith Observatory in exchange for Jenny's life. Just before he is arrested by the FBI and taken to see Hughes, Cliff hides the rocket. Hughes, who has become friendly with Peevy, reveals that the rocket is a prototype similar to one Nazi scientists were so far unsuccessful in developing, to invade the United States. When Hughes demands the return of the rocket, Cliff explains that he needs it to rescue Jenny and escapes, but he inadvertently leaves behind a clue that he is headed to the Observatory.
As The Rocketeer, Cliff flies to the rendezvous. When Sinclair demands the rocket, Cliff divulges to the mobsters that the actor is a Nazi spy; and Eddie turns his guns on Sinclair and Lothar. In response, Sinclair unexpectedly summons 60 heavily armed Nazi S.A. commandos hidden nearby. The gangsters are held at gunpoint as the Nazi Zeppelin rigid airship Luxembourg appears overhead to evacuate Sinclair and his associates. Suddenly, FBI agents announce their presence, having surrounded the area; and they and the gangsters find themselves joining forces to battle the Nazis. Sinclair and Lothar escape the shootout with Jenny aboard the Zeppelin.
Cliff uses the rocket pack to reach and board the Zeppelin; but, during the ensuing showdown, Jenny accidentally sets the cabin on fire with a flare gun. Sinclair takes the rocket to save himself, unaware that Cliff loosened the chewing gum patch. Just after takeoff, the rocket catches fire and crashes, killing Sinclair. Lothar is engulfed in flames as the Zeppelin explodes, but Cliff and Jenny are rescued at the last instant by Hughes and Peevy in an autogyro.
Hughes later presents Cliff with a brand-new Gee Bee racer - and a fresh pack of chewing gum. As Hughes leaves, Jenny returns to Peevy with his rocket blueprints that she found in Sinclair's villa; and Peevy decides that, with some modifications, he can build an even better one.
In 2019, Cliff has presumably died of old age, but his jetpack is discovered by Kit Secord, who becomes the new Rocketeer.