Factual error: In the film during the opening credits, John Reed is traveling by stage coach from Boston to Texas. So what is his stage coach doing driving through Monument Valley that is in the northern part of Arizona? That stage coach is truly lost.
Factual error: During most of the close action shots of Perseus flying on Pegasus, you should see some wing expansion, but do not - only during the wide pan claymation shots.
Factual error: The spotter pilot is Captain Tucker of the Royal Canadian Air Force. But the RCAF of the 1930s used RAF ranks. He would actually be a Flight Lieutenant.
Factual error: The training set piece is supposedly Japan, but it's obviously taking place in the Philippines. Its biggest giveaway is the presence of Taal Volcano.
Factual error: When Henry Fonda and Katherine Hepburn are filling the boat up with fuel early in the movie, when the gas pump is shown, Henry Fonda is looking at the pump. $19.00 is the total sale but 29+ gallons purchased, at .67+ cents per gallon... The total sale should be over $19.43, probably closer to $20 but I can't read the fractions of gallons or cents. (00:14:10)
Factual error: Right after the opening credits, captions say "Susan's house - 1961." And right afterwards, the model train runs by two cigar boxes, one of Dunhill n.25 (seemingly one of the later designs of the box) and the other of "Joya de Nicaragua", a brand founded in 1968. (00:01:25)
Factual error: The elephants in the movie are Indian elephants, not African ones.
Factual error: Ragtime is set in 1906. Yet a 1915 Model T figures prominently in the plot.
Factual error: After the giant egg 'cracks' open on the ground below, Atouk and his men move in for a closer look, and then begin eating the contents. Seconds later the black caveman slips and falls into the "yolk" and then begins dancing around as they cheer him on. When in fact, the boiling steam would've burned him.