Continuity mistake: When Christian Slater and the ranger are radioing for help in the ranger's truck, the enemy helicopter comes from behind a ridge and shoots at them. They get out of the way, and the bullet fire continues and hits the truck on the driver side door, the roof above, and then the ground after that. In the next scene, you can clearly see bullet holes on the hood, going from front to back, but the fire was from right to left.
Factual error: The United States Air Force does NOT, ever, allow its pilots to box competitively! Ground staff, yes; pilots, no, never. A pilot can be suspended from flying if he/she receives a blow to the head in day-to-day life; boxing is right out. Almost all air forces (the RAF included) impose this rule.
Other mistake: When Terry stands in the valley and the stealth passes above her, you can clearly see that a part of the B2 disappears behind a mountain that is several kilometers away before it has flown just a hundred metres away from Terry.
Continuity mistake: When Slater has captured the Hummer, Travolta slams into Slater's car which wrecks the right front light. Seconds later when Travolta arrives at the mine the front light is in one piece.
Continuity mistake: Near the end of the movie, the underground nuclear bomb is detonated, creating shock waves and rippling in the ground beneath the Hummer getaway vehicle. The ripples are huge and come in waves, yet when the explosion subsides, and they drive away, the dirt road isn't rippled or disturbed at all.
Continuity mistake: Toward the end of the movie, after the nuke has been armed in the mine and both groups are driving Hummers, John Travolta switches off the engine and informs his passengers that when the nuke goes off, the electro-magnetic pulse (EMP) will disable any vehicle that is running. Little does John (and apparently the movie's director) know, but EMP will fry any and all electrical circuits, whether or not the vehicle is running.
Continuity mistake: When Hale shoots into the train from the helicopter, he wounds Deakins in the right arm, but later during the movie, the wound is nowhere to be seen. Especially during the fight scene at the end when Deakins takes off his jacket. There's no blood or wound anywhere on his right arm.
Continuity mistake: After the nuclear bomb is detonated, the helicopter spins out of control and crashes in front of the Hummer. Moments later, a camera shot from behind the Hummer shows the road in front of it to be clear, and the Hummer drives away without the helicopter being anywhere in sight.
Continuity mistake: In the closing fight sequence between Slater and Travolta, Travolta takes out a $20 bill, folded, and sets it under the remote for the nuke. Later, when they show the remote again, the bill is shown unfolded, in fact it is flat. When Christian picks the scorched bill off of the plant it is still flat.
Continuity mistake: When Hale throws the gas bomb at Deakins' hummer, you notice that the damage to the right side of the front end from Kelly ramming the other hummer is magically gone.
Plot hole: Slater decides to render the nuke inert by punching in the wrong code three times. However, when he does this, the nuke becomes armed, and Travolta reveals that he is one step ahead by having used a special kind of circuit board to produce this result. Two questions: One, once Slater has armed one nuke, why not arm them all? You've got nothing to lose, and you can keep Travolta from getting them for whatever evil purpose he has in mind. Slater plans to send them all to the bottom of the copper mine anyway, so just arm them all. Two, Travolta later arms a nuke himself, and then smashes the keypad with his gun. Well, if you can do that, why doesn't Slater just smash all the keypads as soon as he gets the nukes? Travolta would be defeated; movie over.
Continuity mistake: When Terry and Hale first meet, Terry says "You're under arrest until we can get this sorted out", and puts the handcuffs on his right wrist. When he kicks her off, the handcuffs are on his left wrist.
Continuity mistake: When we see Terry again after her escapee in the river with Hale, her hair and clothes are in perfect shape. Did she have a comb and hairspray on her?
Continuity mistake: When Kelly fires at the hummer, you see that he punctures the gas tank. On hummers, the gas tank is in the middle of the underside. What he shot was the floorboard.
Continuity mistake: The mine is 600 meters deep. Deakins offloaded the bomb at ground level, started sending the elevator down, and then dropped two hand grenades down the shaft. In the next clip the elevator is at the bottom of the shaft, and the grenades hit the bomb. For that to happen the elevator must have free-fallen to the bottom, not descended as we see it.