Continuity mistake: When John Candy and Steve Martin are travelling from Jefferson City, Missouri to St. Louis they are seen crossing the Mississippi River to enter downtown St. Louis. This would not have been possible unless the bus driver overshot the entire city and ended up across the river in Illinois.
Factual error: At the very beginning of the film during the boardroom scene, Steve Martin checks his plane ticket. Departure time on ticket from NYC is 6:00pm. Arrival time to Chicago is 6:45pm. Travel time from NYC to Chicago is approximately 2.5 hours. Arrival time after time zone change should be approx. 7:25pm, not 6:45 pm. (01:31:25)