Trivia: In the scene after the plane lands in Wichita, Kansas, when the announcer comes over the loudspeaker look at the destination on the flight info display. It says "nowhere".
Trivia: When Neal's wife is watching TV in bed, she is impossibly viewing the John Hughes film "She's Having a Baby," which didn't even premier in theaters until February of 1988, three months after "Planes, Trains and Automobiles" premiered in November 1987. John Hughes (who directed both films) used his own unreleased "She's Having A Baby" footage/soundtrack and a cameo by Kevin Bacon as teasers for the upcoming 1988 film. There's still some speculation that the plots of the two films actually intersect, and that Kevin Bacon (who is credited as the Taxi-Racer in "Planes, Trains and Automobiles") was playing his character, Jake, from "She's Having a Baby."
Trivia: There is a short scene after the credits. You may have to go back to the beginning of the movie to understand the joke.