Control Flight is an intrinsic that causes sources of levitation to instead let you fly. This allows you to grab items off the ground or to descend stairs and exits (such as from the Abyss) without landing first.
All draconians have Control Flight innately. Tengu receive it while using their unique flight ability, but not when using other sources of levitation. Other characters can acquire it by wearing the unrandart Amulet of the Air or by casting Flight.