Factual error: At the end of the film Rainwood has established his innocence of the drug charges and is happily back at work as a senior mechanic for a large airline. However, part of the sentencing and plea bargain protocols at his arraignment is his previous conviction on a lesser drug charge years before. It goes without saying that he did not advise his employers of this when he started work for them - no airline in the world (even pre 9/11) would hire someone with a drug conviction on their record! Now this is out in the open the airline knows that Rainwood is a convicted drug user (on the lesser, legitimate charge) and that he lied on his original job application. They wouldn't hire him again to sweep the floors.
Factual error: The film takes place in a private boarding school the 1950's, however one of the students is studying from a 1980's chemistry textbook. The obvious giveaway is that the spine of one book shows HBJ as the publisher. Jovanovich was not added to Harcourt Brace until the 1970s.
Factual error: George comes up with the idea to raise money via a public share issue in Channel 62 around mid-morning, and promptly announces the telethon on the air and by midnight of the same day they have the money they need. One problem. Even if George had access to a compliant attorney and Channel 62 was already a company authorised to issue shares, a public issue would take at least ten days to organise. There are all sorts of notice periods and filing dates to which the share issuer must adhere. I know - I've done it.
Factual error: In the assault on Fort Wagner, the regiment attacks the fort from the wrong side. In reality, the troops attacked from the south.
Factual error: Budapest didn't exist in 1489. The cities of Buda and Pest weren't combined until 1873.
Factual error: Hooch is a french mastiff. The dog he gets pregnant is a collie. Different breed dogs do not make purebred puppies. Hooch's pups would be part collie, part mastiff. In the end of the movie, one pup is pure mastiff like hooch and 4 are pure collies like their mother.
Factual error: When Harry and Sally are driving away from the University of Chicago at the start of their road trip there is a long shot of them driving on Lake Shore Drive, but they are heading south towards the city with the lake on their left. If they were leaving the city from UofC, which is in Hyde Park, they would already be driving away from the city on Lake Shore Drive.
Factual error: In the beginning sequence where they show the sperm first fertilizing the egg, it is biologically incorrect - only the head part of the sperm enters an egg, everything else stays on the outside and eventually dies off.
Factual error: [Special Edition] The Statue of Liberty is incorrectly shown to be facing the Narrows bridge.
Factual error: When they are at the Cadillac dealership, taking delivery on a car in 1956, the American flag in the background is incorrect. It should have been a 48 star flag, not a 50 star flag.
Factual error: When Bill and Ted grab Beethoven, we are shown the piano he was playing which is a Steinweg (Steinweg later changed his name to Steinway when he immigrated to the United States). Steinweg made their first piano in 1835, and the model shown was built in Braunschweig so must have been made after 1858, but Beethoven died in 1827, years before a Steinweg piano existed. Also the onscreen graphic says it's 1810. (00:47:50)
Factual error: The motel's billboard advertised HBO, which did not exist in 1971 when the movie was set.
Factual error: While Fletch is riding with the bikers, they stop at a stop sign where a family in a station wagon roll up their windows in fear. A sign at a service center in the background is the Castaic Junction, which is in the greater Los Angeles area. The movie is supposed to be taking place in Louisiana. (01:12:35)