Continuity mistake: When John Candy and Steve Martin are travelling from Jefferson City, Missouri to St. Louis they are 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.
Suggested correction: I agree with the original post. However, there could be several possibilities for this scenario: 1. Road closures, 2. Road construction, 3. Accidents, 4. Detours, and 5. Heavy "holiday traffic" could have contributed to the bus having to enter St. Louis from the east despite coming from Kansas in the west.
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)
Suggested correction: There is an upstairs. You enter the terminal on the ground floor and go up for security and the gates.
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)
Suggested correction: Unsure about plane travel time in the 80s. But it currently takes 90 min to travel from DC to Chicago, and the airlines usually add a buffer. So this trip would most likely arrive at 6:30 CST, and a 15 min buffer time would still be reasonable (6:45 pm). For example, my plane tickets usually say estimated flight time of 1:45 or 2 hrs, but when the air currents are normal, it takes 90 min. DC is slightly further south than Chicago, while NYC is slightly further north.
Suggested correction: Considering from Los Angeles-Chicago is a 4-hour flight, and LA-New York is a 5-hour flight, I don't see how it could take 2.5 hours between New York and Chicago. Seems like 1-1½ hours is more accurate.
Plot hole: After the car burns, and they arrive at the motel, Neal only has $17.00 on him and nothing but melted credit cards, forcing him to give up his watch to help pay for the room. Del only has $2.00 but his watch doesn't quite flip the bill. At this point, between Neal and Del, they only have $2.00. However, when Neal invites Del into the room, so he doesn't freeze to death, they are eating Doritos and drinking shooters. Even in 1987 Doritos and a bunch of shooters must have cost more than $2.00. This is assuming Del didn't already have them in his trunk. But even if he did, at the end, Neal gets on his train, makes a return trip to find Del just where he thought he'd be, and then they'd both have to get back onto that train. After all, they both showed up at Neal's home. Once again, It would take money to get on that train. Four train fares with only $2.00. Neal's first trip, return trip, and Neal with Del for the last trip = four fares.
Suggested correction: Del sold shower curtain rings for cash again; it just wasn't shown in the movie.
