Factual error: When Edward Bloom hits the winning shot in the basketball game, a three-point line is visible at his feet. The three-point line was not introduced until the 1970s in the newly formed ABA. It did not reach high school basketball gyms until the late 80s. (00:20:55)
Factual error: When Ewan McGregor's young wife is hanging clothes in her backyard, a small digital satellite dish is visible on the rooftop of one of the houses in the background. This isn't something that should seem out of ordinary, except for the fact that the events in the scene were supposed to be taking place during the Korean War. These dishes weren't commonly seen on rooftops until the mid to late 90s. (01:14:00)
Factual error: When Edward Bloom and Norther are about to rob the Texas bank, you can see the Texas flag over Bloom's shoulder. The flag is upside down, the white should be on top while the red is on bottom.
Factual error: When Edward Bloom is parachuting on his secret mission, he is wearing a British parachute harness.
Factual error: When Danny DiVito tells Edward that his future wife goes to Auburn, he tells Edward to hurry because the semester is almost over. Up until about 5 years ago, Auburn was on the quarter system. (00:59:50)
Factual error: As Jenny Hill is signing over the deed of her land and house to Edward, you can see that the recording location (Volume, Page) is filled in. Also, the County Clerk's seal has been applied at the bottom of the document. In truth, this is the last step. The County Clerk will never see this document until all signatures have been gathered, and only at that time will the recording location be known. (01:42:25)
Factual error: Just before Edward Bloom parachutes on his secret mission during the Korean War (1950-1953), he looks at his wristwatch. The camera shot of his wristwatch shows the second hand advancing one entire second at a time, indicative of a quartz watch. The quartz watch would not be invented until 1960 by Bulova. Prior to that watches used an escapement movement in which the second hand "tics" at a finer and smoother rate.
Suggested correction: Remember that what we are seeing is William's mental picture of the stories his father told him. He never lived in a time without watch movement like that and therefore would think it moved like that.