Goofs

After Cliff puts on the rudder helmet so he can steer/control the rocket, he is frequently seen turning his head without changing his course or direction.

The color of the endcap on the Gee Bee's control stick changes from red just as Cliff takes off to yellow after he flies over the car chase.

After the GeeBee is hit by the fleeing thieves, the long shot shows oil splattered on the windscreen. Then a close up shot shows the windscreen clean before it is sprayed with oil, then it switches back to the long shot with oil on the windscreen again.

When Cliff says, "How do I look?", the chinstrap on his helmet is undone, but immediately afterwards, when Peabody says, "Like a hood ornament," it is fastened.

When Peevy first places the wad of gum on the rocket for "good luck", it is dead center on the rocket pack. The next time we see the pack up close, in the attic, the gum has moved to the right.

After Cliff's Gee Bee R-1 racing plane is damaged, as he is attempting to land we see the engine temperature gauge indicating the engine is overheating. While the engine was shown being damaged, the R-1 was powered by a Pratt & Whitney R-985 Wasp Jr air-cooled radial and could not be overheating as airflow at the 200 mph it was flying would keep the engine cool. The oil pressure could have dropped, but the engine would not have overheated in flight - overheating would only be caused by running the engine on the ground for an extended period of time.

When Cliff is flying around the South Seas Club, his rocket pack lights several fires, and yet his pants and boots never seem to suffer any affects from the heat.

In 1938 Howard Hughes did not yet wear a mustache.

Even with flame-resistant pants, the intense heat and exhaust gases from Rocketeer's jet pack would likely cause severe burns and other injuries.

The orchestra in the South Seas Club appears to be intended to be the Artie Shaw Orchestra, based on the arrangements for "Begin The Beguine" and "When You're Alone." However, at the end of Sinclair's and Jenny's silent dance, the orchestra comes back from break and starts into "In A Sentimental Mood," a Benny Goodman number.

When Sinclair ignites the rocket pack to escape the zeppelin, the rocket exhausts are aimed vertically yet Sinclair travels horizontally. Actually, he is slightly tilted, which does give him a slight horizontal push (given the pack's demonstrated power even the slightest tilt would do the trick). Moreover, the zeppelin itself is moving too, so Sinclair's horizontal movement is at least partly due to the relative motion to the zeppelin.

The word "commando" was not widely used until 1940, after the need for quickly deployed raiding forces arose after the fall of France. The term was coined during the Boer War (1899-1902), however, to describe Dutch Afrikaner long-range penetration units fighting the British, so its use in 1938 is conceivable.

When Sinclair destroys the "LAND" of the "HOLLYWOODLAND" sign, steel frames are holding the letters. In 1938, the frames were wood, the steel was added only in 1978. Furthermore, the LAND letters stood until 1949, but that knowledge is part of the gag.

During the airplane race, a shot of a group of the planes shows no pilots sitting in them, revealing that the airplanes are models.

There are numerous times when the rocket pack exhaust should have burned pants, bed sheets, vegetation, interior walls, truck beds, and many other items.

When Peevy uses the gum to seal the leak in the jet pack, the gum would have been hard and not malleable and dry. It could not have been re-stuck to the jet pack without being softened in some way.

When the abandoned outlaw vehicle races across the airfield, the gasoline tanker blow up before being hit by the vehicle.

As the Rocketeer comes in for a landing at the Griffith observatory, the cable guiding the stuntman to the ground is visible.

Set in 1938 but mentions the Deutschmark, which weren't introduced as the West German currency until 1948. German currency, up to and including the Nazi era, was the Reichsmark. The term "Deutschmark" may have been used, despite the anachronism, for its double-D alliteration, as Campbell's line is "He pay you in dollars, or Deutschmark?"

Multiple uses of the Walther P38 pistol. While the P38 was type-accepted in 1938, due to design issues production didn't start until 1940.

Multiple uses of German MP40 sub-machine gun. The movie is set in 1938, and while the immediate predecessor of the MP40 was designed in 1938, production started late in 1938 and would not have been available.

In the first air show scene (and later in the nightclub), press photographers have 4"x5" Speed Graphic press cameras of a post-war model with the polished aluminum (shiny) lens boards. In 1938 they would have had black painted wooden lens boards.

The final scene shows a stop sign that is white letters on a red background. The White-On-Red color scheme was first mandated in the 1954 revision of the MUTCD, Manual of Uniform Traffic Control Devices, section 29. Before the war, the sign would have been black letters on a yellow background.

When Lothar asks "Where's the rocket?" his voice doesn't match the movement of his lips.

When the GeeBee crashes, you can see the cable which pulls it along. The cable pulling the car into the gas truck can be seen as well.

When Cliff rides along on the ice sculpture, the wheels underneath can be seen briefly.

Howard Hughes destroys the plans for the "rocket" pack, despite the fact that a small air breathing alcohol powered jet engine/rocket could have many uses other than as a rocket/jet pack, and if it is scaled up would have even more uses.

When the Nazi agent is yelling at Sinclair, he shouts, "Ich habe meine Bestellung, und du auch!" ("I have my order, and so do you!") The German word for a military order is "Befehl." "Bestellung" is the order you give to a waiter.

When Malcolm is flying the 'Miss Mabel', Cliff tells Peevy that he, Malcolm, has not been behind a stick in 25 years. Set in 1938, that would make it 1913, pre-dating Malcolm's flying against the Red Baron over the Ardennes in WW1.

During filming of "The Laughing Bandit," the first ruined take has Sinclair saying, "None other" then stabbing the villain. The second take reverses the order before being ruined.