This invention concerns a sound proof hangar for airplanes with a wide entrance (3) for aircraft (7). To provide a sound barrier at the open side, the entrance opening is limited, at least on one side, by a series of deflecting surfaces (10), the inner edges of which are directed, in horizontal section, towards the hangar interior and the external edges of which are directed laterally. The deflecting surfaces (10) can be moved between a closed position which partly or completely closes the entrance opening (3) and a position which opens the entrance opening (3).