A device for an aircraft moving in an air mass relative to a terrestrial frame of reference. The device can estimate at least one characteristic of a displacement of the air mass relative to the frame of reference. The device receives an element of information about the speed of the aircraft in the frame of reference, receives at least one element of information about the speed of the aircraft in the air, and obtains the characteristic from the speed information elements. The device is capable of receiving an element of information about the angle of attack (α) of the aircraft in the air, and is capable of determining the characteristic on the basis in particular of the angle of attack information element (α).