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This film marks the only time that Star Trek (1966) has ever been directly referenced in a Disney film. Co-writer Chris Matheson's father Richard Matheson wrote The Enemy Within (1966).
Although Jason Marsden is a talented singer, he did not perform the musical numbers in the film. It was out of Disney's concern that a Broadway-style musical actor should provide Max's singing voice instead. That actor was Aaron Lohr, a personal close friend of Jason's. However, two decades later, at the 2015 D23 Expo, during a panel celebrating the film's 20th anniversary, this was rectified when Jason Marsden and Bill Farmer sang a duet of "On the Open Road" together without any prior rehearsing.
When Max is singing in the school auditorium, Roxanne's position changes from close to the stage to the back of the room. The reason the filmmakers did this was to give the illusion that all Max cares about is Roxanne and no one else.
Donald Duck originally had a larger role where he played a travel agent. Goofy asks "What do you think I should do?" Donald responds incoherently. Goofy responds, "What did you say? Is there someone else I can talk to?"
Pauly Shore asked for his role to be uncredited, because he didn't want Disney to sell the movie on his name similar to Robin Williams' request for Aladdin (1992).