Factual error: The vents that Hunt and his sidekick crawl down at CIA Headquarters are standard galvanized steel box vents; they are very common in the building trade. Try walking or crawling down one - you'll make a noise like the sky is falling down. People will be able to hear you for miles. Every person in that building would know somebody crawling about in the vent system. (This error applies to dozens of films, not only this one).
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: The United States Air Force does NOT, ever, allow its pilots to box competitively! Ground staff, yes; pilots, no, never. A pilot can be suspended from flying if he/she receives a blow to the head in day-to-day life; boxing is right out. Almost all air forces (the RAF included) impose this rule.
Factual error: In the begining when Jo's dad is bringing the family downstairs and say's "TV says it's big, might be an F-5" That scene was set in 1969. In reality he would not have known anything about an F-5 or any tornado with an F rating because the Fujita scale was not developed until 1971. (00:02:45)
Factual error: A flight manifest would never state on its seating chart that an armed U.S. marshal was on board as it gives away that person's identity and puts everyone on board in danger.
Factual error: It is stated that Miss Trunchbull competed in the Olympics in shot put, javelin, and hammer throw. According to her jersey those were the 1972 Olympics. The hammer throw wasn't added as an Olympic event for women until 2000.
Factual error: The actual Tsavo lions responsible for the killings had no manes - see for yourself; they are on display at the Field Museum in Chicago. [The filmmakers employed artistic license in using maned lions. They were also certain to include - at the very end of the movie - footage of the real Tsavo man eaters, as they appear in the Field Museum.]
Factual error: The portrayal of the firing MLRS before Denzel's unit moves off is ludicrously inadequate. The rockets launched from the MLRS resemble a space shuttle lift-off, but in the movie it was more like a sparkler thrown into the air.
Factual error: When Howard is running after the bouncy ball he is on the second floor of the Mall of America, however, you see him run through the LEGO store which is located on the lowest floor of the Mall of America, which is impossible if he was on the second floor before.
Factual error: Even aside from the ridiculous recoil that a railgun would cause (yeah, I know they don't use gunpowder, but there's got to be SOME opposite movement, surely), how come when the darts (bullets, whatever) go straight through people, they still get thrown backwards? The passage straight through them means minimal energy being transferred to them, and as such they shouldn't be hurled backwards that much.
Factual error: When the plane is taking off while the animals are on the runway they duck down hoping it will stop and it becomes airborne shortly before hitting them. In actuality they should have been blown backwards from the jets like ragdolls.
Factual error: When the submarine rises in the waters of Norfolk and you see Norfolk in the background, there is one blatant problem. There are NO mountains in Norfolk. Most of Norfolk, Virginia, is below sea level.
Factual error: After Hardy dies and they're going through his possessions, a football scarf is pulled from his kit bag. The scarf has a Sunderland AFC badge. The film is set in World War II. The badge on the scarf was introduced in the 1970s.
Factual error: When Goodspeed crashes the Ferrari, his airbag deploys and he must shoot it to get out of the car. In reality, airbags inflate and deflate again in less than a second - the gas escapes through vents or the material itself, so there's no way for one to stay inflated.
Factual error: When the boys have a night on the town with a bunch of eager Dutch girls, the girls somehow forget their native tongue and start to chatter in Danish.
Factual error: During the movie, which is based in '79, Roy has a Rhino bowling ball. Rhinos weren't made until '85.