As the boys look through the junkyard for the pieces for their ship, Rosebud (the sled from Citizen Kane (1941)) can be seen sitting at the top of a pile.
The film was in a prolonged editing phase when the studio moved up the release date. The theatrical release was the result of accelerated editing and was not finished to the director's satisfaction. The studio told the director Joe Dante that he was finished and they were going to go ahead and release what he had at that point.
When the helicopter pilot looks at the newspaper, one of the headlines says "Kingston Falls 'Riot' Still Unexplained". Kingston Falls was the town where the events in Gremlins (1984) (also directed by Joe Dante), took place.
The sound effects from the movie at the drive-in were taken directly from the original 1982 Atari 2600 video game Yars' Revenge (1981).
Robert Picardo says the alien makeup is the most uncomfortable he has ever worn. The Wak makeup was like having a typewriter balanced on his head and the father was like balancing a television. Whilst the crew were enjoying lunch he would have to sit there and take the pain which drew him to tears and actually caused open lesions on his head.