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The names of people who worked on this movie appeared several times. On the first issue of "The Chronicle" that reports the docking of the Hindenburg III at the Empire State Building, multiple headlines contain references to Kerry Conran and brother Kevin Conran (headline "Conran Ministry Force Deal"), Darin Hollings ("Dr. Hollings Speaks"), Omar McClinton ("McClinton seeks license to halt sanctions"), Brian LeachZack Petroc ("Leach and Petroc Break Over Budget"), and Stephen Lawes ("Lawes Held Ready to Aid U.S. Peace Action"). In the issue of "The Chronicle" with the headline "Giant Machines Steal Refineries", the article is shown to be written by Marsha Oglesby, one of the executive producers. Although dim lighting makes it practically invisible in this movie, there is a list next to the giant wall map in the Flying Legion base, which contains the last names of several crew members.
As Sky Captain and Polly Perkins fly submerged with "The Amphibious Squadron", they "overfly" a sunken steamer named "Venture". It's the ship used to bring King Kong (1933) to New York City. It even includes, on its deck, a cage large enough to confine Kong; implying perhaps that this is the original Skull Island.
The "World of Tomorrow" portion of the title is a reference to the 1939-40 New York World's Fair, which was named "The World of Tomorrow".
While the project was still in early development, writer and director Kerry Conran originally wanted to produce it as if it were a lost serial from the 1930s, with the movie featuring unknown actors, shot in black-and-white, and divided into chapters, each ending with a cliffhanger. All of these ideas were subsequently abandoned in an attempt to gain bigger box-office appeal.
The Giant Robots that attack New York City are an homage to the "Superman" cartoon Superman: The Mechanical Monsters (1941). In both instances, the robots were remote controlled by radio signals.
When Polly is on the phone to her editor, reporting the advance of the giant robots, her line is "They're crossing Sixth Avenue... Fifth Avenue... they're a hundred yards away...". This is a direct lift from Ray Collins' lines in Orson Welles' "The War of the Worlds" broadcast of 1938 as Collins plays a reporter on the roof of "the Broadcast Building" reporting the advance of the Martian tripods.
Matthew Feitshans: The production supervisor played the officer who informed Sky Captain of the approaching robots when he and Polly arrived at the Flying Legion base.
Kerry Conran: the German-speaking porter in the opening blimp interior scene, who takes a note from the scientist.