Abstract: Apparatus for improving aerodynamics of a freight tractor-trailer combination, having at least one of the following: a series of retractable roller-mounted screens connecting the rear of the tractor with the front of a trailer; a fairing fixed to each side of the trailer near the front of the trailer, and which is adapted to fit about the rear wheels on the tractor when the tractor and trailer are connected, such fairing extending downwardly from the trailer side, and extending rearwardly towards the center of the trailer underside; a pair of laterally spaced fairings connected to the underside of the trailer about the fore and aft rearmost pairs of wheels, each of said fairings having an aerodynamic rounded forward edge, and a rearward taper to a rear point; an air deflector positioned at the bottom rear of the trailer, and having a slight upsweep to direct air passing beneath the trailer to a distant centerpoint to the rear of the trailer; an upper baffle at the top of a rear roll-up door on the trailer