Not totally wrong, it depends on which part of the system you are referring to. The prop has done work on the air. W=FxD, F=MxA, the prop has accelerated a mass of air from one side of the prop to the other, but if you consider the airplane, which has mass, acted upon by an acceleration (gravity), then the prop has done no work (in this case) on the airplane cause the thing hasn't moved any distance.
Evan, WB#12.