Factual error: In circling over Washington Dulles, a plane would fly over several airports that they could land at with perfect communication, including Richmond, Baltimore, Andrews AFB, etc. Also, there is no communication from the airport to the plane but the plane would be in range of no fewer than 15 transmitting stations that could have relayed messages.
Factual error: During the opening credits, the show's copyright date is shown in Roman numerals as MCLXIV. In Arabic numbers, that's 1164 - it should have been MCMLXIV for 1964.
Factual error: No airport in NYC has the view of the New York City skyline that Kevin has when he realizes that his family is in Florida and he's in New York.
Factual error: Jonathan is lying in the middle of the skating rink when the second cashmere glove falls upon him. Looking around, he notices Sarah at the edge of the rink. Despite Sarah being a female and the fact that it is snowing, even Nolan Ryan would have a difficult time throwing something as light as cashmere that distance. (01:22:05)
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: Throughout the film, characters are able to break through on radio transmissions and speak to the other person talking, and the other person would hear them. In reality, they would have to wait until the first transmitter un-keyed the radio before any other discernable radio traffic could have be heard. (A good example of this is the scene where Ellis is giving up McClane.) (01:18:40)
Factual error: One of Angel's lyrics (in "Today For You, Tomorrow For Me) refers to the movie "Thelma and Louise." Rent (the movie) is set in 1989-90. "Thelma and Louise" was released in 1991. This was caused when they did the move from Broadway to the screen. The stage show did not specify the year. So when they adapted the stage show to the movie, they didn't check the references. Plus it just sounds cool. (00:28:25)
Factual error: While travelling up the east coast from FL to ME they show a Santa Fe passenger train, which only runs out west.
Factual error: When Iris is unable to sleep she looks over at Amanda's bedside clock which displays 5:00 pm, however, moments later Iris discovers a button to lower the shade. There is bright sunlight coming into the room, however, in December the sun sets prior to this time (about 4:45pm according to timeanddate.com)
Factual error: On Day 3, look at The Embrey Star newspaper when it zooms into the headline. Above the headline is the newspaper's web address, hardly appropriate given the paper is from 1980.
Factual error: When Santa is shown the miniscule print on the 'Santa Clause' card (that he is supposed to be/get married) the Elf holds an enormous lens in front of it, to make it easier for Santa to read the print. From the distance Santa is standing at, from his point of view the card should appear upside down.