Disclosed is a set of aerodynamic surfaces for an aircraft. There is included in the set a fixed aerodynamic surface delimited by two external walls which, at the rear, converge toward one another. A mobile flap extends the external walls, forming a mobile trailing-edge. An actuator is positioned so as to cause the mobile flap to rotate. A vane runs in the overall direction of the span of the fixed aerodynamic surface, and rotates with the flap.