The alien character played by Mandy Patinkin was originally going to be named George Jetson but Hanna-Barbera wouldn't give the rights to the name. The decision to call his character 'George' in the movie was kept as an in-joke.
Jerry Goldsmith's synthetic and score was rejected early in post production for being "too weird" and replaced with music by Curt Sobel. Jerry Goldsmith's rejected score was released in Spring 2005 as a Varese Sarabande CD Club Release limited to 3000 copies.
The October 1987 draft of the screenplay credits a rewrite to James Cameron. He is not credited in the final film.
The trailer shows a portion of a fight scene between George and Rudyard Kipling with a burning car in the background, meaning that in an earlier edit Kipling exits the car before it explodes (you see him regain consciousness at one point with a groan) and then fights with George. This would also explain why it is that Sykes compliments George on showing "some good moves back there".
When George is comforting the old woman a poster of former boxing champion Sugar Ray Leonard can be seen hanging next to the Pepsi cooler.