The question about hot-air balloons* got me thinking: What do you call their type of movement in English? In German it is not "fliegen" (flying) but "fahren" (shipping, possibly driving). What is it in English?
*: Balloons which are unpowered, without engines or propellers; they can only move up and down due to buoyancy changes (lifted by helium/hydrogen/hot air) and are otherwise at the mercy of the wind.