Other mistake: When the bus starts to leave the Hoover dam (as seen through Dallas' binoculars), the driver is missing. The steering wheel is shown with no-one behind it.
Other mistake: When Howard is running behind the car driven by the lady in the fur coat, he's always shown directly behind the center of the car, but when the lady looks in her side mirror (from her point of view), Howard is in the center of the mirror. In reality, she would only see a part of Howard's left side in the reflection (not his whole body).
Other mistake: When we see the front page picture of Mike with the alcohol and joint, he's pouring the alcohol over his bottom lip and chin, going down the front of his shirt. This doesn't match what we see him do. It does appear that Mike spilt alcohol on himself when off camera, but the wet spot is on the right side of his jacket, but not down the front.
Other mistake: In the beginning, Albert Brooks and Lisa Kudrow are eating dinner at a restaurant and Albert mentions his books, plural, but then he says book, singular. All the way he's said book, so what is it - books or book?
Other mistake: During the ending US Supreme Court scene right before Alan Isaacman proceeds with his opening statement, Larry Flynt can be seen standing up instead of in a wheelchair. (01:55:53)
Other mistake: After they cross the water their clothes appear dry.
Other mistake: It's said to be winter there, what looks like snow is shown in the sister's yard yet for two days Alex goes out in a mini skirt.