Abstract: This invention pertains to the reduction of air drag on trucks and truck tractor-semitrailer combination vehicles when they are driven on open highways. It consists of a short thick airfoil mounted by struts above the cab of the using vehicle. The airfoil is made by forming upper and lower surface skins by conventional means of metal or plastic and joining them with internal ribs. Metal or plastic struts are used to adjustably attach the airfoil to and above the cab of the using vehicle. This invention uses both the upper front and the lower rear surface of the airfoil to create air flow patterns which result in reduced air drag. This invention may be used with vehicles of different sizes and may also be oriented so that it does not increase air drag when used on a truck tractor which is either traveling with no semitrailer or is coupled to a low or flat-bed semitrailer.