From Bulbapedia, the community-driven Pokémon encyclopedia.
The Sky (Japanese: じょうくう Sky) is a location in Pokémon Ranger: Guardian Signs. As the name suggests, it encompasses the skies above the Oblivia region. It can be accessed by using a Staraptor's Field Move, Fly, or summoning Latias/Latios via Ranger Sign.
Pokémon captured here can be brought onto land by talking to Supurna at the dock of Aqua Resort on Sophian Island.