Factual error: Finishing his rounds on the morning of Christmas Day, flying over downtown Chicago, the sun is over the horizon west of Chicago, Sunrises occur in the east, not the west. (00:26:10)
Factual error: Neal says he stopped believing in Santa Claus when he was three because he didn't get an Oscar Mayer wienie whistle. You didn't have to buy wienie whistles; the Oscar Mayer company gave them away to children for free at grocery stores. (I had one.)
Suggested correction: For a child believing in Santa, it's not the price of the gift. His parents didn't get him a weenie whistle for whatever reason, even though he asked Santa for one.
Factual error: Tim Allen drives a 1st generation Ford Taurus SHO (1989-91) in the movie, which was only available with a manual transmission. When he pulls up and parks at the Denny's, you can see his hand down on the console and the clicking sound of shifting an automatic from drive into park.