A wind turbine having at least a blade comprising a first component having an aerodynamic profile with a leading edge, a trailing edge, and suction and pressure sides between the leading edge and the trailing edge, and a second component, attached to the trailing edge and/or to the leading edge of the first component in at least a part of the blade. An upwards and/or downwards deflectable flap allows changing the flow over the blade, in which the unit for deflecting the flap is a fluid inflatable unit placed in a flap inner chamber close to the first component and in which the wind turbine comprises a unit for controlling the inflatable unit depending on the wind situation and/or the blade loads.