The invention relates to an aircraft (10) provided with: a wall (14) having an exterior surface in contact with air flows external to the aircraft, an internal cavity (16) in the aircraft, recessed relative to the exterior surface of the wall, at least one mobile trapdoor (18, 20), which in closed position prolongs the exterior surface in such a way as to shut off the cavity from the exterior, and which in open position projects relative to the exterior surface in such a way as to open the cavity to the exterior, characterized in that it is provided with at least one mobile aerodynamic deflector (30, 32), whose movement is slaved to that of the said at least one trapdoor, the said at least one aerodynamic deflector projecting relative to the exterior surface in a zone thereof situated outside the zone covered by the said at least one trapdoor when the said at least one trapdoor is open.