Factual error: While handling the ignition coil cable to the distributor cap, Joe Pesci tells De Niro that the timing chain needs adjustment in his truck. A truck of that year with an inline Chevy motor would not have a timing chain at all, instead this truck would be equipped with a direct drive timing gear. Even if it had a timing chain, it would be behind the water pump and a cover. It would have been a several hour job to replace, not possible to adjust it.
Factual error: The interior shots of the Gemini and Apollo Spacecraft show worn and dirty panels, knobs, switches and circuit breakers. The movie most likely used some original cockpit trainers, but in reality the astronauts were flying brand new spacecraft that were spotless.
Plot hole: When the group is walking through the jungle for the 2nd time, they have nothing more than their backpacks and a horse to accompany them. Suddenly we see them rowing down a river on a boat and raft. After making peace with the savages, when they have to let a group member go to get medical help, they have been washed ashore as they have been traveling on a single raft since the canoe was damaged by spear attack. How is it that they had a horse and an Indian guide to send away with their injured man? (01:16:55)
Revealing mistake: How on Earth can Selby get those skin tight T-shirts over that huge cast on her arm? They cannot possibly stretch any more than they already are - look at the scene where she and Eileen are checking the mail. There is no way that sleeve would fit over the cast without ripping! It is well beyond the capacity of that tight T-shirt to stretch to that extent! Obviously Christina Ricci had the cast fitted after she was in costume.
Factual error: In a scene in 1980, Brian May is teaching everyone the beat for his new song "We Will Rock You." However that song was released in 1977.
Factual error: Robert McNamara is wearing a multi colored Polo shirt talking to Mrs. Graham in 1971. The Ralph Lauren Company did not make the shirts until 1972.
Factual error: In the scene where the Navy Seals are riding in the cars, the VA state vehicle inspection can be read from behind. It read "6 13" for June 2013. This would have been correct for the period the film was made, but not for the time of the incident.
Factual error: When Mark types email addresses in to tell people about facemash, he writes to several people @harvard.edu. At the time the movie takes place, undergraduate email addresses were all of the form email@example.com. Furthermore, the network brought down by facemash would have been referred to as the FAS network. (FAS stands for Faculty of Arts and Sciences; the eponymous network covered all buildings within the College and Graduate School of Arts and Sciences.).
Visible crew/equipment: At the beginning of the film when being rescued from the quicksand you can see someone's legs and hand behind the horse, holding it. (00:10:00 - 00:11:00)
Factual error: On the plane, while being escorted by FBI agents, Frank Jr sees New York's LaGuardia Airport and says, "There it is, LaGuardia Airport, runway 44." A runway numbered 44 is impossible. No runway can be numbered over 36 because there are 360 degrees in a circle. (01:58:25)
Factual error: It's late 18th, possibly early 19th century and, as Jane and her sister walk along the beach, a construction crane is visible on the horizon.