Continuity mistake: In the opening scenes where the are driving home and the right front tire goes flat. Just before the Big rig truck hits them you can see that the tire is not flat. (00:07:50)
Continuity mistake: When the red Ford Bronco is driven off the ferry (ignoring all the impossible factors required for it to successfully do so), it flips through the air and contacts the water going backwards, its right/rear tail light entering the water first. The closer next shot shows the truck sink somewhat as it continues to flip backward, onto its roof. The very next shot shows the interior of the truck as it enters the water right-side up and going forward as water rushes in. Denzel lurches forward and down, driving his face into the water that is about waist level. The next exterior shot is underwater as the truck now lands in the water, nose first and right-side up. It then begins the expected slow dive, nose-first. (01:52:30)
Continuity mistake: In the scene where Superman is trying to prevent the plane from crashing he is holding the nose of the plane and bits of it start to crumble in and fall apart or away. Once the plane is safely on the ground within the ballpark the scene shows the plane from the side where there is no damage to the nose. (00:40:15)
Factual error: Take a look at Google Earth - the section of the Golden Gate Bridge Magneto breaks off (about a mile - tower to tower plus a section each end) isn't anywhere near long enough to reach Alcatraz from anywhere on the mainland.
Continuity mistake: When Barris is served in the diner, french fries are scattered over his plate. When seen again, the french fries are replaced with vegetable sides.
Continuity mistake: Near the end of the film, Violet infiltrates the complex and makes her way into a white room with tons of men in white suits. She starts fighting them and when a couple of guys come at her, she moves quickly and one guy stabs the other in the chest. When she goes to elbow one of the guys in the face, watch his helmet, it comes flying off, revealing his head and hair. When the camera quickly changes to another angle, his helmet is on perfectly straight. (01:17:45)
Continuity mistake: During the last few scenes in the movie, when Hannah asks Jenny if she needs help with the plane, they knock knuckles together. When the shot is taken from behind Hannah, she is shown wearing gloves, but when the shot position changes to behind Jenny, the gloves magically disappear.
Continuity mistake: In the shot where Mattie walks towards the toilet at her school, you can see there's a pencil in her hair pointing downwards. When she's inside the toilet, the pencil's direction and her hair have both changed.