Continuity mistake: At the end when Clear is in the car, trying to get away, she knocks over a can of turpentine. When you look at the can again it has changed the way in which it fell.
Continuity mistake: In the scene where Alex is watching the TV on how the plane exploded, look at the illustration shown. Then compare it with the illustration that appears on Alex's computer screen. The positions of the explosions shown are different. (00:50:42)
Continuity mistake: When Ms. Lewton dies, she is grabbing her bleeding neck with her left hand. While walking into the kitchen, she leans onto the kitchen table with her right hand. Later in the scene, when Alex comes and tries to help her, we see the bloody left hand impression on the table, even though we should see the right one.
Continuity mistake: Late in the film, Alex Browning hides out in the cabin and attempts to make it as death-proof as possible, securing everything therein with ropes and duct tape, and carefully placing his kerosene lantern in a tray of water. At first, we see that the antique lantern is painted dark green; but, one scene later, the same antique lantern (in the same tray of water) is now painted bright red.
Continuity mistake: In the scene where Billy gets his head sliced off by a piece of metal that fell off the train, as his head rolls away his hair is a much lighter shade of brown than it was during the rest of the film.
Continuity mistake: When Alex is talking to Clear in her garage, one strand of her hair keeps changing, first curled under, and then straight, back and forth...
Continuity mistake: Near the beginning, when they are at the Memorial for the school, look closely to the right of Devon Sawa right after he and the other gal look at one another - an extra with red hair walks in front of him, in the very next shot Devon gets up, and the same extra is now behind him.
Continuity mistake: When you see Alex watching the news report about the crash of 180, after coming back from the airport, you see his mum and dad asleep on the couch with a pillow at the end of his mothers foot and a few shots later after hearing the loud thunder, the pillow is lying on her ankles.
Continuity mistake: After Alex reads his porno and throws the magazine at the owl, that one piece of paper with "Todd" pops out of the fan after the magazine got stuck in it. Now, this is a very small mistake, but if you look at the shape of the piece of paper, the one short stump side changes between takes. Like I said, it's very small differences, but there are differences.
Continuity mistake: A reporter takes a photo while Clear and Alex talk at the memorial. When we see the photo in the article, it's at a different angle and Alex has vanished from where he should be next to her.
Continuity mistake: Alex buckles his seatbelt when he first sits down on the plane, before the girls ask him to move, making him have to unbuckle to move for them. When he wakes up after his premonition, he immediately jumps out of the seat, not buckled in.