When footage is shown of the Langley Research Center we can see a fuselage of an A-320, an aircraft not built until 1989.
After Norma's Father runs Arlington's license plate number, he refers to the vehicle as a "Town Car".
It's actually a Buick Electra.
When being followed down through the corridors of the library, they enter a main hallway where it shows his followers coming from two different directions.
Yet just a second before all five of them were coming from the same direction as he was.
When Walter and his 'nanny' decide to go down the basement, he allows her to go in and down the stairs first.
In the next scene, when they have come down the stairs and into the basement, he is seen coming down those stairs first and his 'nanny' follows.
After Norma's Father runs Arlington's license plate number, he refers to the vehicle as a "Town Car" but Lincoln did not come out with the "Town Car" until 1981.
Up until then, and in the year this movie takes place, the use of "Town Car" was only used to denote a trim package on the Lincoln Continental.
Someone referring to a Lincoln in 1976 as a "Town Car" would make no sense.
It would be like describing a car as "sport package" or telling someone "It was a Ford 'Luxury Edition'".
The stop for Santa standing in the middle of the road ringing a bell.
Santa is brightly illuminated by their headlights.
After the truck hits them they go back to Santa, still ringing the bell and still illuminated by their headlights.
'Cameron Diaz' (qv)'s "Southern" accent comes and goes throughout the movie.
Takes place in Virgina, but Virgina cars have front and back plates.
During the NASA presentation near the start of the film, the projected image from behind the speaker is visibly pixelated.
This would only happen with a digital projector, which didn't exist in the 1970s.
When Norma's watching television early in the film, a commercial comes on advertising the debut of the sitcom "What's Happening!!" The date was earlier established as December 16, 1976, when Arthur attends the Viking seminar.
"What's Happening!!" actually premiered on August 5, 1976.
The license plats show 7 characters.
In Virginia, in 1976, the auto license plates had larger letters/numbers & were always 3 letters with 3 numbers, also with a month sticker on the upper left with the year sticker in the upper right of the plate.
Some of the cars in this movie show 7 number/letter combinations in a smaller "font" and with only a year sticker.
(at around 1h 25 mins) You can see the white dots used by the CG (Computer Graphics) department to make the scar appear on Arlington Steward's face.
Multiple times a map is show with a portion labeled CENTCOM.
US Central Command was not established until 1983, while the film takes place in 1976.
911 emergency services weren't available in Fairfax County until 1981.
Dana's motel room has a door with a lock requiring a magnetic stripe key card.
While the magnetic stripe concept has existed since 1960, it would be extremely unlikely to see a motel with such a lock before the late-1990's.
Arthur Lewis received the envelope from NASA at the office informing him that he had been rejected from the program, but when he comes home his wife holds the envelope and already knows the news.
Arlington Steward's world map shows Eritrea as a state.
Eritrea was a province of Ethiopia from 1952 to the independence in 1993.
