At the beginning of the movie, Neal Page (Steve Martin) races a character played by Kevin Bacon for a taxi. Later, Neal phones his wife to tell her that he has been delayed (again), in the background, you can hear the fight from She's Having a Baby (also directed by John Hughes) between Bacon and Elizabeth McGovern, when she screams that she doesn't like his friend's girlfriend.
At the beginning of the movie when Steve Martin (Neal Page) races Kevin Bacon (Taxi racer), is a direct reference to the scene in the movie Quicksilver in which the character played by Bacon is racing someone on a bicycle.
The scenes at night on the higway were filmed in central California. Fake snow was applied to the sides of the roads to make it appear as a Midwest winter.
The Marathon Car Rental scene is exactly one minute long from the time Steve Martin starts his tirade, to the time the attendant ends the scene. In that 60 seconds, the word "fucking" is used 18 times.
Cast and crew traveled from the Midwest to the East Coast and back in search of snow for many scenes, which seemed to melt whenever they arrived. The shoot was hellish, and according to some who worked on it, Hughes's grumpy behavior (he was going through rough times) only made it worse.
No transportation company wanted to appear inept or deficient in any way, so crews had to rent twenty miles of train track and refurbish old railroad cars, construct a set that looked like an airline terminal, design a rent-a-car company logo and uniforms, and rent 250 cars for the infamous Rent-a-Car sequence.
Neal's house was also a set built from scratch, consisting of seven rooms and taking five months to complete. It ended up costing $100,000, which angered Paramount executives and caused turmoil on the set.
Although it's not included in the theatrical or the network cuts, a shot of Del Griffith brushing his teeth was included on ads for the network version.
John Hughes' original choice for the train station and platform was the station in Kankakee, Illinois, 60 miles south of Chicago. The cast and crew were in town for a week waiting for weather cold enough to make snow... and several interior scenes were filmed at an abandoned warehouse using a "cover set".
John Hughes shot over 600,000 feet of film, almost twice the industry average. The rumored three-hour version of the film does indeed exist, although not in order - moreover it's a mess of footage that would take "months, maybe even years" according to Hughes to transform into an actual film. It is locked away in a Paramount vault, and according to Hughes, most of it has probably deteriorated by now.
The green convertible is a 1986 Chrysler LeBaron Town and Country, with a 2.2 Turbo engine, it was modified for the film, including the following Dodge 600 parts: tail lights, steering wheel, and owner's manual (that can be seen in the glove compartment when Neil puts his wallet in there) the trunk was off of an older K-car convertible: no third brake light, and the luggage rack that was not offered in 1986 but was on older ones
John Candy and Steve Martin eat dinner on the plane in a scene that is not in the theatrical version though it airs on the televised version. The scene ends with a long-haired passenger in front of Steve Martin letting his or her hair cascade down onto his brownie, completely covering it. No longer hungry, John Candy fishes through the hair to retrieve and eat it.
In the airport scene in Wichita, when the airline employee announces that the flight has been canceled, you can see on the board behind him that the destination of the flight is "nowhere".
Del Griffith's friend at the railroad, Bert Dingman, is a direct reference to Robert O. Dingman Jr., President of the New York and Lake Erie Railroad where the train scenes were filmed.
The scenes shot at Lambert Airport in St. Louis were shot during winter but the weather was uncharacteristically warm (mid 80's F), so all the snow in the scene had to be trucked in.
A scene that is not included in the movie but featured in the trailer shows Del (John Candy) in the bathroom of the first motel he and Neal (Steve Martin) are staying in. In the scene he does, among other things, an impersonation of Elvis Presley in which he sings into his hair brush.
The house used as Neal's family home is actually in Kenilworth on Warwick. The home used in "Home Alone" was on Lincoln Ave. in Winnetka, one town over.
In a BBC program about playing with the Steep Canyon Rangers broadcast late 2009 in the UK, Steve Martin in a interview said that John Hughes had told him he wrote the script in 3 days.
John Hughes in an interview on the 'Those Aren't Pillows' DVD edition was inspired to write the film's story after an actual flight from New York to Chicago he was on was diverted to Wichita Kansas, thus taking him 5 days to get home.
John Hughes wrote the first-draft of the screenplay in 3 days. His average writing time for a screenplay in those days was about 3-5 days with 20-some rewrites.
Steve Martin was convinced to join the production after favoring two scenes he had read from the script; the seat adjustment-scene in the car, and the F-word tirade at the car rental desk.