Continuity mistake: Concerns the helicopter carrying Bob Bishop to the White House. The helicopter is shown as having a wheel-chassis during the approach to the landing-site, and skis in the precise moment of landing.
Factual error: There is a chase through the Archives-Navy Memorial station on the Washington, D.C. Metro, but the station looks nothing like the real one and the trains don't look like the trains on the DC Metro.
Continuity mistake: During the course of the movie, an assassin leaps onto a ragtop Jeep driven by Givens (Linda Hamilton) in order to kill both Bishop and Givens. To get rid of the assailant, Bishop (Charlie Sheen) unlatches the ragtop and it separates from the Jeep, taking the assailant with it. The movie is pretty good about maintaining that the ragtop is lost from that point on. However, when Bishop and Givens are in her apartment later in the movie, government satellites are searching for her Jeep. When the satellites find and zero in on the Jeep, the ragtop is in place (look on the monitor following the tracking of the satellites).
Continuity mistake: After buying the sunglasses and baseball cap, Bobby sneaks into the church alongside the nuns. Then we see four cars pull up beside the van and agents exit, but on the monitor that Grasso is watching only three cars full of agents have pulled up to the van before those agents exit.
Continuity mistake: When Bobby is reversing in the Crown Victoria to try and escape the sniper, he leaves the driver's door open and it gets bent into the fender by a parked car but is still attached. In the very next shot, the door is completely removed from the vehicle.