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.
Factual error: In the scene at the Braidwood Inn, after Neal shakes Owen's hand and the shot is of Owen with the freeway in the background, you can see a Jays Potato Chips truck drive past. The inn is supposedly near Wichita, Kansas. Jays Potato Chips were not sold west of the Mississippi at the time.