the casting 358 the end cap 322 widens along its upper surface to provide an airfoil surface which curves in an arcuate manner as it traverses from front to rear the arcuate matches the curvature of the underside of the blade 312 a pair of apertures 360 in the end cap 322 align with a pair of apertures in the blade 312 to receive a pair of fasteners such as rivets or the like to secure the blade 312 to the pivoted end cap 322 the blade 312 projects transversely beyond the end cap 322 providing a wider surface to deflect air downward across the rear light of the automobile the end cap 322 can also be affixed to the blade 312 by adhesive bonding or the like fig1 illustrates an additional embodiment of the present invention wherein the blade is hinged from the cross strap of a luggage bracket a lower edge of the blade 412 rests upon a projection 418 of the support 414 when the vehicle is at rest or there is insufficient velocity of the vehicle to raise the blade 412 from its at rest position referring now to fig1 wherein there is illustrated an embodiment of the present invention with the pivoting blade assembly mounted to the frame of the rear light or alternatively mounted to the vehicle body adjacent the rear light a pair of castings 558 are fastened to the vehicle frame or the frame of the rear light a pair of end caps are hingedly attached to the castings 558 and support therebetween a.