Doraemon the Movie: Nobita's Sky Utopia

synopsis

In Doraemon the Movie: Nobita's Sky Utopia, Nobita, Doraemon, and the rest of the gang set out on an adventure in search of the sort of legendary utopias like Atlantis or the Dragon Palace beneath the sea that people have been dreaming about since ancient times. With the help of a time-traveling ship, they discover Paradapia, a civilization of floating islands where everyone lives happily and everything is perfect...or so it seems...