The aviators in the plane during the "On the Good Ship Lollipop" song were all volunteers from the football team at the nearby University of Southern California.
In the 1970s, Jane Withers told author Marjorie Rosen that she had gotten the part in this film as a result of an open audition. All the other girls who auditioned had been carefully coached by their parents to act sweet and nice, trying to out-Shirley Temple Shirley Temple. Withers' parents were smarter; they realized that if Fox wanted another girl Temple's age for a Temple film, it would be to play a bad girl to Temple's good girl. So they coached Withers to play bad, and she got the part.
Director David Butler auditioned over thirty girls for the role of snobby Joy Smythe. When he heard Jane Withers' imitation of a machine gun, he signed her on the spot and sent the rest of the girls home.
Shirley Temple's mother Gertrude Temple worried that Jane Withers would steal the spotlight from her daughter, and she tried to convince director David Butler to minimize Withers' role. Butler refused, saying that Withers' bratty, spoiled character would increase audience sympathy for Shirley.