The final scenes of the film see Martin’s character Neal realising Del’s (John Candy) wife has been dead for years, and he was simply trying to occupy himself by helping with Neal's plight.
Martin and Candy famously got on extremely well during the filming of the movie, and began a strong friendship afterwards.
Just seven years later, however, Candy died of a heart attack on March 4, 1994.
In an excerpt from the book Wild and Crazy Guys: How the Comedy Mavericks of the ’80s Changed Hollywood Forever, author Nick de Semlyen looked into the backstory of Planes, Trains & Automobiles, and how it affected the actors’ lives.