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.
Other mistake: Sergeant Johnny Gallagher (Gene Hackman) and Lieutenant Milon Delich (Dennis Franz) are in a supposedly deserted building searching for a group of conspirators who plan to assassinate both the USA and USSR presidents. Delich finds a police colleague of his in the building, and Delich kills his colleague. When he fires his revolver, the sound of the blanks can be heard, slightly out of synch with the gun blasts on the sound track.
Revealing mistake: In the scene after the battle of Agincort, where Henry and his retainers are walking meditatively among the heaps of the fallen, if you look carefully, you will see one of the fallen with his head raised watching the procession. He then realizes that he is on camera and puts his head back down. It's near the edge of the screen so may occasionally be cropped.
Continuity mistake: In the scene where they are discussing why Dalton fired Mr Wesley's nephew (upstairs in the Double Deuce). Mr Wesley's nephew threatens Dalton with a knife and when Dalton takes a swing at him, there is blood on Mr Wesley's nephew's face way before contact. (00:34:05 - 00:38:00)