Continuity mistake: When David is explaining to the President about the aliens' intentions with Earth's satellites, he draws two lines that start at the destroyer and go off straight both edging off Earth. But when he places the paper back on the desk to draw in the satellites, the left lines have risen away from the Earth. (00:41:00)
Character mistake: In the Iraqi Desert, when the British soldiers speak of the casualties and losses, one of the British soldiers mentions the loss of the Belgian contingent and possible reinforcements, then makes a reference to the "Golan Straits"; there is no such place.
Factual error: When Russell enters his F/A-18 during the final assault, he pushes the keypad "8" button out of curiosity and it inadvertently arms a missile. In reality, the keypad buttons are merely for navigational purposes and map coordinates. They would never be tied to the weapons system. (01:59:15)
Other mistake: When the President and the others arrive at Area 51, the sliding glass door to the laboratory that the staff member opens with his key and numerical key code opens before he finishes entering the code.
Visible crew/equipment: When President Whitmore is on the phone with his wife (their daughter Patricia lies on the bed), telling her he wants her to leave LA and a chopper will take her to Nellis Air Force Base, a Secret Service Agent appears at the doorway and the actor's mark is visible on the floor. (Only visible on fullscreen DVD.)
Visible crew/equipment: When David introduces the idea of a virus, the first time Major Mitchell shoots at the Coke can the two actors' marks are visible on the floor in front of Julius and Connie, as well as a brown rug at their feet, that are not in other shots. (Only visible on fullscreen DVD.)
Factual error: The firewall that destroys Washington DC is all wrong. When the destroyer blows up the White House, as in NYC and LA, it would have created a ring of fire that would have spread outwards. The White House is in a North Westerly position from the Capital Building, so when the fire wall hit the Capital Building, it would have hit from the side - but, instead, it hits from the back/front. (00:47:30)
Factual error: The missile launched by the B-2 is made-up. The nuclear missiles carried by the B-2 are powered by a small jet engine, not a rocket motor. The last air-launched, rocket-powered, nuclear missile was withdrawn from USAF service in 1990, before B-2s had even been delivered to the Air Force. Plus, these missiles are very accurate and have a range of hundreds of miles. Why get so close? Finally, the B-2 pilots have no flash blindness protection. No blackout panels on the windows, or special goggles that darken when exposed to bright light. The tinted visors on their helmets isn't good enough to block out the flash from a nuclear detonation. (01:36:20)
Continuity mistake: When David squeezes his dad's shoulder, after he just won chess, David has a severe bruise on the middle fingernail of his left hand, which disappears as soon as he gets back to work.
Factual error: When Air Force One is taking off, the fireball should not be that close. The heat from the fireball would keep the wings from getting any lift as hotter air is thinner. Since the fireball is hot enough to explode steel and concrete it would surely have ignited the 45,000 gallons of fuel in the wings and melted the rubber tires. Had the plane actually been able to get its tires off the ground, the 'rolling' effect of the fireball and the rapidly rising heat being below and behind the plane would have caused it to do a 'negative angle pitch-over' or forward somersault right into the runway.
Continuity mistake: In the Oval Office, when David says, "They're using our own satellites against us," the grandfather clock is about a foot away from the doorway behind him. In the previous wideshot, when Alex appears at the doorway, the grandfather clock is farther to the right, nearer to the other curtained doorway.