Abstract: An aerodynamic drag reduction fairing is mounted on a substantially vertical rear surface of a vehicle. The fairing body comprises a generally inverted U-shaped member with a transverse top portion and a pair of depending legs upon the top and sides respectively of the rear surface. The body has a surface which is contiguous with the outside surface of the vehicle at the top and sides and then converges in a curve shape inwardly and rearwardly to a trailing edge spaced rearwardly of the rear surface. The spacing of the trailing edge from the rear surface is greater at the top than at the bottom of the sides legs. From the trailing edge the body extends back to the rear surface to form a hollow interior inside the top portion and the legs. This can be inflated so that the body can be formed from a flexible fabric.