Revealing mistake: When John is fighting in the baggage area and he and the bad guy fall off one of the conveyors, you can see it is not Bruce Willis as he's falling. (00:15:00)
Other mistake: When the platform falls on top of McClane and he drops his gun, I don't see how it would land more than six feet away from him. One foot at the most. Unless of course it was made of rubber. (00:47:05)
Plot hole: When McClane gets kicked out of the control tower and is sent down in the elevator with Coleman he quite obviously stops the elevator before saying "Here's a couple of words, F**k off." to Coleman. He then opens the top panel and climbs out WITHOUT restarting the elevator. Almost as soon as he has closed the panel again the elevator has reached the bottom and the cops are asking "Where's the other one?" As it is meant to be a single shot and there is no delay we know Coleman did not start the elevator again herself. (00:38:25)
Factual error: When McClane lights the fuel with the zippo, the flame trail is all wrong. There appears to be a thin strip of fuel which accelerates away from him. However, we have seen the Fuel spurted out in a wider less controlled manner from a wing tip that has to be at least fifteen feet up, in a wind, which would have sprayed it around further. There is no way it would light in the tight manner shown. (01:45:55)
Suggested correction: The fuel would not light at all, so the tightness of its trail is really unable to be determined in this manner. Assuming jet fuel could light like that, it's possible that only the densest area would be able to catch, which would be the center of the trail... but again, Jet A is pretty hard to catch on fire.
Factual error: There is absolutely no way that Bruce Willis could have stood in the middle of an airport landing zone trying to keep the plane from crashing into the ground. He has no protective ear equipment on - that noise most definitely would have blown his eardrums out and blew him several yards away physically when it flew over him.
Continuity mistake: In the beginning of the film when two of Stuart's men arrive at the church, their van stops and it is not snowing outside,same thing when they're shown knocking and then when the man opens the door. However, in the shot just after (which is taken from behind the door) snow is falling on them. The shot then switches to an outside view ,and it's not snowing anymore .
Deliberate mistake: At the very end, John McClane lights the fuel trail which subsequently engulfs the plane. To do this, he tosses a lighter onto the trail which begins six inches from where he lies, having fallen from the wing while pulling the lock off the fuel dumper. Trouble is, the fuel began flooding out at the same time he fell, and the velocity would carry him some distance forward on the ground after he lands (which it visibly does); hence, it is physically impossible for him to be in the position he is in relation to the fuel. (01:50:05)
Continuity mistake: When the army truck arrives at the 747 hangar, we see a line of snow on the ground behind it. The actual truck has no snow on it at all, despite its journey to the hangar.
Suggested correction: Snow doesn't generally accumulate on a moving vehicle. Anything resting on the vehicle will blow off once it's in motion unless it's very wet and/or heavy.
As a truck driver, I can tell you that the conditions shown would have snow accumulating on a moving vehicle at least in some places.
Factual error: The first shot of the church is a high up shot which pans down as the van enters the shot. High mountains can be seen in the background. The film is set in Washington D.C. (Note: the film was shot in the Denver area.).
Revealing mistake: Right after they realise they have to get the planes in a holding pattern to clear the runways of snow, you can see a shot of Holly's plane. This is a model (Look at the clouds; they don't change shape that fast) and the fact that the lights on the wings are flipped. The right wing always has a green light, the left wing always has a red light. In this shot, the lights are reversed but not the logo. So it's not a mirrored image; it is a model. Also the lights on the top are LEDs in a strip. (00:27:38)
Factual error: There is no Glock 7, and Glocks are produced in Austria, not Germany.
Revealing mistake: When the terrorists cut the pipes with wires behind the church, one guy uses a chainsaw, and the pipes he cuts are all empty.
Continuity mistake: While Barnes is brainstorming ideas with his staff about using the marker beacons to communicate with the circling planes, he has a pen in his right hand held to his face. The next shot he turns, but the pen is no longer in his hand and his hand is nowhere near his face.
Audio problem: When McClane goes to Lorenzo's office for the first time, we hear Lorenzo say "who is it? Come in." His lips don't move (which you can tell despite his mug being up to his mouth).
Continuity mistake: When the lady sitting next to Holly pulls out her stun gun, her book is resting against her stomach. However, in the previous shot from a different angle, the book isn't seen.
Visible crew/equipment: When we first go to the Annex Skywalk, the SWAT team are walking with the guy from the tower and he is talking on a radio. In the mirror behind them you can see the boom mike and operator as they walk.
Factual error: In the tower, Leslie Barnes and a few men are talking about the Annex Skywalk, mentioning that it is a "VHF System." Barnes says the planes are so close it won't matter. VHF, or Very High Frequency, transmits far distances, hence why it is used by airports around the world. He should have said "UHF", which transmits shorter distances, as that would make more sense.
Continuity mistake: McClane's fireman's jacket gets progressively bloodier throughout the film, but around the time when he is fighting the terrorists on the planes wing, it is miraculously clean again. McClane is not wearing it, but it does get cleaner. (01:45:50)
Continuity mistake: In the airport lobby, when the two policemen come at the bar they have "snow" all over their clothes. In the next shot they are shown from behind sitting at the bar and Lorenzo's brother has no snow on his jacket. Seconds after Mc Clane comes to talk to them and the cop has snow on his shoulders again.
Factual error: A dangerous prisoner like Esperanza would not be flown into a civilian airport. He would be transported to the nearest USAF base, in this case Andrews Air Force base, always assuming that he is being extradited to Washington D.C. As well as this his wrists would be shackled to a chain around his waist which would also be c attached to ankle shackles. He would also be escorted by half a dozen armed police officers.
