Continuity mistake: In the first scene that introduces us to George Clooney's character, we see him in front of some sort of Judicial committee. The first scene he wearing gold leaves which indicate the rank of Major, although in the movie he is a Lt. Colonel. Then very next scene when we see Clooney he is wearing the correct rank.
Continuity mistake: When Julia is giving a brief to the people in the room about terrorists and such, Tom interrupts and walks over to the screen. In this shot Julia is raising her hand/hands and pointing at him, yet in the following shot her hands have not moved from her side only her head has moved to the mic. (00:23:35)The-Immortal
Continuity mistake: In the fight scene between Tom and Alec in the truck that is hanging over the edge, when Tom is pulled up by the helicopter he cuts the rope and lands on his back. He actually loses his knife which is in his right hand, yet in all following shots its reappeared back in his hand. (01:15:05)The-Immortal
Continuity mistake: When the bomber walks on to the streets of New York, he passes a violinist standing next to a tree. There is a man with a red coat sitting on the trees ledge and a black man standing next to him, yet in the following shot (perhaps 1 second later) the man sitting on the ledge and the black man are both standing up about 4 feet away from the tree. (01:33:00)The-Immortal
Continuity mistake: When Tom and Julia are in Julia's office, Tom sits down while Julia is on the phone and begins to read the small card from the flowers. In one shot Tom's three/four fingers are on the back of the card, then in the following shot he is holding the card at the edge with just his fingertips on the card. (00:26:55)The-Immortal
Continuity mistake: In the beginning of the film the Russian officer presses a code on the back of the train carriage to close the door - the red and green buttons are at the bottom of the panel. Slightly later on when the warheads are being stolen, he has to press the code again, this time the red and green buttons are on the top of the panel.
Continuity mistake: When Tom jumps from the helicopter, into the truck that is hanging over the bridge's edge, the rope that is attached to him remains attached until Tom and Alec start fighting. Then it disappears, and suddenly reappears when Alec wraps the rope around Tom's neck. (01:14:05)The-Immortal
Continuity mistake: When the hijackers are setting the nuclear bomb, they drill a device to the face of the bomb, and on the right of the screen there are wires sticking out of the little silver box. In the following shot one of the hijackers opens the little silver box and pulls the wires out again. (00:12:10)The-Immortal