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: 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: 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)
Factual error: Three different characters (including two police officers) describe the car driven by the bad guys as being a maroon Ford wagon. Yet in the two scenes showing the car, it's a Pontiac.
Factual error: The Bat signal at the end would not show up like it did in the film. In order to be as clear as it was, as well as visible, it would actually have to shine onto a surface, not just the clouds. They made this same mistake in Returns, but made it believable in the clouds (just not as sharp) in Forever.