Plot hole: The fact that a five minute timer starts after the three Cerberus codes are entered defeats the purpose of the program. If they program was made to destroy their own nuke warheads in case of a misfire you would expect them to be destroyed as soon as all three codes are in.
Factual error: The cavemen Harrier pilots are shown using the hover mode frequently. Harriers, even with drop tanks as depicted in the film, can hover for at most 5-10 minutes, as the thrust required to keep the aircraft in the air without any lift consumes massive amounts of fuel and overheats the engine, and real-life Harrier pilots are instructed never to hover for long periods of time, unless absolutely necessary. The amount of time the cavemen spent hovering (hiding out of sight in a parking garage, sneaking up on the Psychlo gunships, etc.) would have easily caused their fuel to run dry.Dom
Other mistake: At the carnival, you can see an African-American man staring at the camera for a while. I am unsure if he is a crew-member watching over the scene, or if he is just an extra trying to get onscreen.
Continuity mistake: When Danny gets shot at the end of the film, his paper flies out of his hand. But the very next shot of him shows that the paper is still in his hand being held over his head while he falls backwards. In one of the following shots the paper is back on the floor, but it's on the opposite side it should have been when it flew out of his hand. It's all shown in slow motion and it's very obvious.
Factual error: A force of Russian Tu-22 Backfire bombers attacks the aircraft carrier USS John C. Stennis (CVN-74) by sneaking in under the ship's radar. This is all well and good except that carriers usually don't use their own radar, they have Airborne Early Warning aircraft (E-2 Hawkeye's) that can see much further and not give away the carrier's position (let alone the F-14s which would be patrolling too) not to mention the fleet of destroyers other ships guarding the carrier. The whole point is, the US Navy practiced and planned for such a "carrier versus Backfire" battle for years. I guess in the interest of furthering the plot Hollywood has to ignore the immense measures the USN takes to protect those multi-billion dollar assets, not to mention the 5000+ sailors that man them.
Revealing mistake: In the scene when the main character is in the library on the internet, she goes to a couple of websites. When the shot shows the URL up top, it is C:\windows98\mydocuments\etc.html. Instead of actually searching on the web they used a premade html page and accessed it from their computer.
Factual error: As Ben is clinging to the staircase while it is falling apart, there is a close-up of a nail being pulled out of the wood. This nail is round-headed, rather than square as it would have been over 200 years ago. It's also shiny instead of rusty, which indicates that it's galvanized. Galvanization as an industrial, metal-preservation process was not patented until 1837, and was not used in building materials until well into the late-1800s. Since the film states the staircase was made by "the Founding Fathers, " and there was no galvanization of iron nails in any industrialized nation in 1780s-1830's, this is a huge anachronism.Kristal
Deliberate mistake: When MIB agents exit the lift to get into the main hall of the MIB Office, the lift opens halfway up the wall and they need to go down a little platform. But when K and J return during the lockdown and face the trashcan with guns, the lift opens at floor level, so it can be conveniently peppered with bullets. (01:02:05)
Revealing mistake: In the last scene where Edward and Bella are sitting in the sunny field, Edward is not sparkling. (01:52:55)
Revealing mistake: When Amidala and Anakin are eating and he cuts her a piece of the fruit and "floats" it back to her, the bite appears in the fruit a split second before she actually eats it. [This appears to be fixed in rereleased versions]. (00:53:40)
Continuity mistake: In the 'Gaston' song sequence, near the end, Gaston is sitting in his huge antler chair with Lefou. In the wide shot, there is a bear rug behind the chair. The camera does a close up of Gaston, then in the next wide shot, the chair is on top of the bear rug. Also, after this, Gaston gets up off of the chair and in the next shot, both the chair and the rug disappear completely. (00:29:20)