Abstract: Vehicle Flow Direction Vanes for reducing the rear vacuum induced drag on moving vehicles and thus increase mileage performance on the order of 20 percent. Aft, and forward, mounted flow direction vanes are attached to flat-back vehicles to deflect air flow into the drag producing reduced pressure area rearwardly of the vehicle. The basic shape of the vane is based upon the criteria that a line tangent to the curved surface at any point does not exceed an angle of 30.degree. to the main airstream to avoid local separation.