The role of Speed was intended to be for an exceptionally athletic boy, but when Will Harris auditioned, the Casting Director found him so likeable, that the role was changed to accommodate his larger stature.
Lynda Carter was initially given gold bracelets to wear as an homage to her role from the 1970s television series. Warner Bros., who owns the copyright to Wonder Woman, did not want the bracelets shown in a Disney film, so they were removed from Lynda's wardrobe for the film. Twelve years after this film, Warner Brothers released a theatrical depiction of Diana Prince/Wonder Woman in her solo film for the first time.
The phone number for Stronghold Realty is 800-656-1482, which is a number at ABC, which is owned by Disney. The voicemail message was: "Thank you for calling ABC, the number you have reached is a fictional non-working number used for motion picture, and television production." The number can be seen near the end of the movie when Mr. and Mrs. Timmerman are admiring their new house, which is about to be crushed by Sky High, the camera pans by the Stronghold Realty sign. However, the number no longer gives that message. It now says: "In order to better direct your call, please state the company and the ten digit phone number you are attempting to reach."
The comment Mr. Boy makes, about sidekicks not wearing costumes with colors that clash with their hero's, is a jab at comics' most famous hero/sidekick team, Batman and Robin. Where Batman wears dark colors (blue and gray) Robin wears bright colors (Red, green and yellow).
According to actors who auditioned for various roles in the production, the main children's parts were to be contracted for not only a sequel, but also a possible television series on the Disney Channel.
Each of the main characters has his or her own color scheme, wearing the same colors throughout the movie. Will's colors are red, white, and blue. Layla's is green. Gwen's is pink. Warren's is red and black. Zack's is yellow. Magenta's is purple. Ethan's is orange.
During production, Michael Angarano (Will Stronghold) and Mary Elizabeth Winstead (Gwen Grayson) had a romantic relationship. Meanwhile, Danielle Panabaker (Layla) had a romantic relationship with Steven Strait (Warren Peace). This information can be found in the special features section of the DVD.
There is an Aquabats show poster on the wall in Gwen Grayson's room. On that poster, there are five bands, the Aquabats, the Mosleys, the Moon Monkeys, the Immortals, and My Superhero. The Aquabats are a band made of superheroes. The Mosleys, a garage sounding band, founded by Paul Frank, the same person who founded the clothing line Paul Frank clothing. The Moon Monkeys, a space-surf band consisting of super Chimps in space, The Immortals, a surf-punk band, whose singer also produces and directs low budget science fiction movies, and My Superhero, who's name, by chance, worked well for the theme of this movie.
Near the beginning of the movie The Commander says he had just, "saved the Superdome from collapsing." The movie was released one month before Hurricane Katrina hit New Orleans and severely damaged the Superdome.
Early in the movie, The Commander and Jetstream are called away to deal with "trouble downtown", before Will and Layla leave for their first day. On their way, they have a conversation where The Commander tells Jetstream not to worry about Will, and she says "What if he forgets his lunch?" When the kids leave for the bus, Will doesn't seem to carry a lunch, but has a shoulder bag, so his lunch could be in there, but at lunch he has a lunch tray like the other kids, with what looks like a school lunch, so it appears he did forget his lunch.
The trivia items below may give away important plot points.
Tom Kenny (the voice of SpongeBob SquarePants) and his wife Jill Talley (who voices Karen) make an appearance. They play the man and woman reassuring that they didn't need to buy house insurance, when Sky High is falling down.