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 been aware of the translation, he would not have used it as a title.
Dubbed in 1999, Castle in the Sky did not receive a home video release until four years later when Spirited Away won an Academy Award for Best Animated Film. During that time, it would be shown at the occasional film festival, and sell out with little word-of-mouth. Despite its limited success, Disney's official explanation for the delay was that Studio Ghibli wanted to avoid reverse-importation of the film in Japan and lose R2 sales. However, by 2003, Laputa had long made its money back in dvd sales in Japan, fueling fire to the long-held fan speculation that the company purchased the Ghibli library for the purpose of sabotaging its potential success in the U.S.
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.
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.
Gondoa, the land Sheeta is from, is probably inspired in Svaneti's historic province of Georgia, in the northwestern part of the country. The landscape with mountains, farms, and - most importantly - the typical towers.
Hayao Miyazaki:
[military history]
The weaponry and mechanical settings in Laputa is 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.