Factual error: Listening to a radio broadcast, live, since no other indication is given, Joe Louis is completing the 12th round of a fight. This is December 6, 1941. Joe's last fight of 1941 occurred in September, his next fight was January 1942. (00:00:10)
Factual error: The sun can't rise out of the Pacific ocean when viewed from America, as seen when Danny is playing the clarinet. (00:01:20)
Factual error: In scenes that take place in 1912 on the porch of the hotel you can sometimes see American flags in the background. The flags in the movie have 50 stars. The 50 star flag wasn't adopted until after 1959. (01:25:15)
Factual error: When Loretta and Patsy return from shopping, and Doolittle gets mad about the makeup Loretta is wearing, look closely after they leave Doolittle and you will see a 1965 LeMans among the parked cars. Patsy Cline died in 1963.
Factual error: After Superman accidentally frees the phantom zone villains with the exploding hydrogen bomb, they start flying towards the moon. The sleeves in their clothes can be seen fluttering around. This would be impossible because there is no air in outer space, hence nothing to cause resistance against the clothes.
Factual error: A film about the making of a film. A car is filmed going off a bridge, and the footage is played back repeatedly. Throughout, the car is referred to as a Duesenberg, even though, in nearly every shot, the Mercedes tri-sected circle logo is visible above the radiator.
Factual error: When the Blues Brothers are trying to escape the Illinois Nazis, they are on a freeway heading through a construction site. They break through several barricades, jam on the brakes, and stop just before they go off of a bridge. They slam the car into reverse and flip through the air to escape. The Illinois Nazis go over the bridge. The bridge is in Milwaukee, WI. The tall white building in the background is the US Bank building in downtown Milwaukee, WI. As the Nazis fall to earth, they fall past a building in downtown Chicago, IL before going through the street on impact. The Nazis fell from Milwaukee, WI to Chicago, IL. (02:11:00)
Factual error: During all the major battle scenes involving tanks the Germans are using post-WWII tanks. The turret looks a bit like the M10 Wolverine with a top cover.
Factual error: At the end of the movie, they break out of prison and their lawyer finds them at the hangar. She tells them they are free and they celebrate and get in the car and drive off. Innocent or not, they broke out of prison. I highly doubt red tape would allow an official to say, "Oh well, never mind, we were gonna release them anyway." (01:46:25)
Factual error: The middle third of the film recounts Dr. Thompson meeting Laszlo at the 1972 Superbowl (VI) in Los Angeles, however, in 1972 the game was played in New Orleans.
Factual error: A solid gold cross of the size used in the film would weigh more than what any human could hold in front of them (nearly 200kg), much less as "easily" as the priest did at the end of the movie.