Factual error: If you're a Hertz #1 Club Gold Member like Ryan is, you don't need to swipe your card or sign for a rental as shown in 2 scenes. You just go to your assigned car in the lot and show your driver's license at the exit.
Factual error: When Bingman is shown leaving Detroit, he is in front of a large window with a 747 outside (also the movie cover). This fountain and location is inside the McNamara terminal in Detroit. As he is a million miler with American Airlines, he would be in the other terminal.
Suggested correction: But he is flying with Natalie this time, who is not a million miler.
Factual error: In the first scene that takes place in Ryan Bingham's office in Omaha, if you look out the window, a City of Saint Louis, Missouri flag (red with a blue sort of sideways Y shape on it) can be seen in the reflection of the building across the street.
Factual error: When Bateman orders Clooney and Kendrick to return to Omaha from Detroit, there is a shot of them waiting in the McNamara Terminal. This Terminal, however, only holds Northwest/Delta flights. They would be in new North Terminal of Detroit Metro Airport, since they fly American Airlines.
Factual error: After the rehearsal dinner, Ryan is told to turn up around 5pm for the wedding to start at 5.30pm. In February, sunset is between 5.04pm and 5.42pm for Waupaca, so it would be dark outside, however, when the wedding takes place and into the dinner itself, it is light outside.
Factual error: In the scene where Bingman leaves Chicago after visiting Alex, he is shown riding the airport tram. This tram is inside the McNamara terminal in Detroit.