Factual error: If they are really in the Wichita, Kansas airport, listen carefully to the airport announcements (real faintly in the background). When they say for "Mary Ellen" to meet her party upstairs, there's a slight problem with that. There is no upstairs in the Wichita airport. (00:12:53)
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)
Factual error: In Wichita, when Del and Neal are getting picked up by Owen at the Braidwood Inn, there is a mountain right behind Owen. There are no mountains in Kansas.
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.