Laputa, the flying island, was a setting in Jonathan Swift's novel Gulliver's Travels, published in 1726. Hayao Miyazaki says in interviews that he was unaware that "la puta" means "the whore" in Spanish. If he had known the translation, he would not have used it as a title. Swift, incidentally, is considered the inventor of "black comedy" and, as a well-educated man and satirist, very likely knew the meaning of the Spanish term (in the novel, the Gulliver character lists Spanish as one of the many languages he's fluent in).
The fox squirrel makes an appearance in the garden scenes, scampering on the robot in Laputa's garden. The fox squirrel first appeared in an earlier Miyazaki film, Nausicaä de la vallée du vent (1984).
Laputa was inspired by Paronella Park, a castle built by Jose Paronella at Mena Creek, in Far North Queensland, Australia. The theme music from "Castle in the Sky" is used during the night tours of the castle.
The correct romanization of Sheeta's name would have been "Shita," but the producers of the Disney English dub changed the spelling for obvious reasons.
First film from Studio Ghibli since the opening of the studio in summer of 1985.
Hayao Miyazaki: [military history] The weaponry and mechanical settings in Laputa are a mixture of British and German designs. Miyazaki is a fan of German weaponry (he has manga works like The Return of Hans and Otto Carius - both about WWII German tank crews), so soldier's uniform, medals, and grenades (Stielhandgranate, the famous "potato masher" in WWII) are modeled after German design, not to mention the gigantic battle zeppelin "Goliath." However, since the town of Slag Ravine was modeled after a mining town in Wales, British-styled civilian clothing and British weapons such as Lee-Enfield SMLE Mk. III rifle (soldiers) and Webley top-break revolver (Muska and his agents) appear frequently in the film.
Hayao Miyazaki: [flying] As the title suggests, the castle of Laputa flies. Numerous flying contraptions feature in the movie.