Palamok

Palamok is the Drone homeworld. In the Halo 3 Limited Edition manual, it says that Drones are suited to fighting on the Earth's surface, so it is likely that Palamok is similar to Earth. The multiplayer map Guardian might be set on Palamok, as you can hear the screeching of Drones in the background. The surface of Palamok may be covered in trees if Guardian is set there.

The planet would presumably present some obstacle that would force the evolution of wings on its' inhabitants.