Factual error: Terry-Thomas's plane gets stuck between the carriages of a Paris-bound train (in fact filmed on the single-line track between Bedford and Hitchin). Just before the train plus plane goes into a tunnel you can see the cooling towers of Bedford's Goldington Power Station (circa 1960) behind TT's head. (01:58:20)
Factual error: When the crooks are on their getaway from the bank raid in the hearse, you can see 1960s cars through the back window when this scene was set in 1950.
Factual error: When the race starts, the people are waving American flags with 48 stars: 6 rows of 8 stars each. However, in 1908, when the race took place, there were only 46 states.