Doraemon: Nobita and the Kingdom of Clouds (1992, Shin-Ei Animation)

While learning there are different types of clouds of varying densities, Nobita wondered if there was one big enough for Heaven to exist on. Naturally the entire class laughs at him including Suneo and Jaian so he decides to ask Doraemon for help. Since kingdoms in the clouds only exist in folklore and fairytales, they decide to make...