Factual error: There is a shot of the Imperial Valley at night with the edges of the Los Angeles destroyer spinning over the mountains. The center of the destroyer is hovering over downtown LA. Imperial Valley is over 200 miles away from downtown LA, and the destroyer is no more than 20 miles in diameter. There would be no way the edges of the destroyer would extend far enough to be seen from Imperial Valley as shown unless it was over 100 miles in radius. The ship does not even hover over Steven Hiller's house which is in LA, it can nearly be seen whole from there. The destroyer would be obscured by the mountains and from 200 miles it would appear much smaller.
Factual error: During the final battle over Area 51, Russell Casse appears in his F-18 and states he is armed. After he attempts to acquire radar lock on the alien's primary weapon, he states he is locked on and has tone. He then says the tactical brevity code Fox-2, which indicates the launch of an infrared-guided missile. However, the missile he is actually attempting to launch is an AIM-54 Phoenix, which is an active radar guided missile, designated by the launch code Fox-3. The master monitor display also incorrectly shows the missile mounted on the port wingtip launcher of the aircraft where the AIM-9 Sidewinder would normally be mounted, instead of on the port wing's weapon pylon where the missile actually is. Historically, the F-14 Tomcat was the only fighter capable of carrying the AIM-54, as it was such a heavy missile; the AIM-54 was never used on the F/A-18. Instead, they carry the AIM-120 AMRAAMs, not the AIM-54 Phoenix that were shown in the film.
Factual error: The Capitol's dome crumbles like stone, but it's made of iron. (00:48:10)
Factual error: When Steven Hiller is flying through the canyon he says "Hope you got an air bag" and pulls a lever to deploy the braking chute on his FA-18. The chute is then detached and lands onto the attacking alien craft. FA-18's don't have a braking chute, they rely on using an arrestor hook for carrier landings and a dorsal airbrake when landing on a runway. (01:00:50)
Factual error: When Jasmine is running in the tunnel, she kicks open the door just in time to save herself, her son, and the dog. The terrible fireball then goes right by them. They are just inside the open door, with fire and debris flying right past it. While the fire and debris might not spill in, the heatwave would still fry them. It is also likely that the fire would deplete the limited oxygen of the enclosed space. (00:49:50)
Factual error: David and Julius are traveling south to DC from NY so David can tell the President about the alien's plans. At one point, they're inside the city and the U.S. Capitol building is directly in front of them. This shot is famous because many movies have photographed the Capitol building from here. To get to this point in their travels they would have, in all likelihood, passed right by the White House since they are heading south on Pennsylvania Avenue towards the Capitol Building.
Factual error: In any explosion the shock-wave will travel ahead of any debris thrown by the shock-wave. During the attack scenes there are numerous cases of debris, particularly vehicles, travelling and landing in still air ahead of the arrival of the shock-wave.
Factual error: When the alien ship over New York blows up the Empire State Building you see the blastwave spill out in the street in front of the Empire State Building. This is in that part of the city that's built in a grid pattern. In front of the Empire State Building there's just another building, not a street where the blastwave and debris can spill into. All the people who are way down the street, looking at the building being hit by the beam just can't be there. (00:47:00)
Factual error: The US Bank Tower's placement in between Citi Group and Melon Bank is inconsistent from its real life position. Citi Group should be roughly directly parallel, not off-center at an angle.
Factual error: When the aliens attack Novosibirsk, Russia, a map of "Russia" in Russian letters is displayed on-screen from what is supposed to be a Russian news broadcast. In fact, it's a map of the Soviet Union, St. Petersburg is incorrectly labeled as "Petrograd," Moscow is too far east, and Novosibirsk is very badly misspelled. (00:15:20)
Factual error: In the opening scene, the plaque from the Apollo 11 landing is shown sitting in the lunar soil. The actual plaque is mounted to the landing module, right under the ladder. (00:01:00)
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)
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.
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)
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 opening scene shows the Apollo 11 landing site. Aside from the previously mentioned plaque incorrectly shown being on the ground, the scene shows a pristine American flag standing upright. The Apollo 11 flag was actually knocked over when the Lunar Module ascent stage launched. Plus the American flags left on the moon are bleached white with no color, due to UV rays and massively direct sunlight - and they are probably disintegrated, due to micro meteors and solar destruction. (00:00:45)
Factual error: When the alien ship arrives in Washington DC, its shadow goes over the Lincoln Memorial from the bottom of the Lincoln statue to the top. Since the saucer is heading over the National Mall and the Lincoln Memorial faces the Mall, the shadow should have gone from the top to the bottom. (00:21:40)
Factual error: David is in New York playing chess and then goes to the station riding his bike through the office. When he goes past the vending machines, the water machine is Arrowhead branded, which is a California / west coast water brand - not on the east coast. (00:07:00)