Factual error: When Roberts makes a deal with the Captain, he demands that the Captain grant liberty to both sections (i.e., the entire crew), leaving only Roberts and one enlisted man aboard as the deck watch. All U.S. Navy ships must have enough personnel aboard at all times to get the ship underway immediately, if necessary, which is why the crew is divided into watch sections.
Factual error: When Jimmy Stewart is almost down to the runway during the bad weather, the aircraft exterior shots show the type of cloud tops found only at high altitude, not low to the ground.
Factual error: The opening scene shows Spencer Tracy on a crack streamliner in the desert east of Los Angeles, featuring red and orange coaches. Such equipment was used by the railroad on only two trains, neither of which crossed the desert east of Los Angeles, and both of which had matching red and orange locomotives. In the film the train is pulled by a dark gray locomotive normally used only to haul freight, and in a close-up shot the number in the locomotive is preceded by an X, which in the language of railroading refers to an extra train.
Factual error: One of the shots of individual British Lancaster bombers approaching one of the dams is actually and incorrectly an American B17, seen for only a second or two. [At no time in the film is a B17 visible in the British release of the film. However the B17 crashing appears in a version of the film released in the U.S.A.]
Factual error: Towards the end of the film, the German troops are searching for the marines and cross from the dockside to lighters and then on to a harbour launch. Although this is supposed to be in Bordeaux the launch is marked 'PLA' or Port of London Authority where the action must have been shot.
Factual error: When Kitchener is shown inspecting Harry's old regiment, one group of African or Egyptian troops is shown to be wearing the Pattern 1914 Infantry Equipment, not made until 1914 at the earliest. Additionally, it has the 1918 modification to have two closing straps, so is over 20 years too late for the 1894 date at that point.Andrew Upton