We describe a data analysis technique for determining gravity wave intrinsic parameters including wave propagation direction. The technique involves measuring the altitude variations of the wave-induced density perturbations of the atmospheric Na layer. This technique can be used with airborne lidars, multiple ground-based lidars, and steerable lidars. In this paper the technique is applied to airborne Na lidar data obtained during a roundtrip flight from Denver, Colorado, to the Pacific Coast in November 1986. During the flight, strong wave perturbations were observed in the Na layer near the Pacific Coast over a horizontal distance of nearly 700 km. The intrinsic horizontal wavelength of this wave was estimated to be about 85 km, and the vertical wavelength was 4.1 km. The intrinsic period was about 102 min, and the propagation direction was almost due south. ¿ American Geophysical Union 1990