We present kinetic energy horizontal and vertical wave number spectra of wind and density perturbations at midlatitudes for the altitude range from approximately 80 to 100 km. The spectra are inferred from Na density profiles collected with an airborne lidar during two flights conducted in November 1986. The two flights included one round trip from Denver, Colorado, to Springfield, Illinois, and another round trip from Denver to the Pacific Coast. The horizontal wave number spectra exhibited an approximately kh-1.2 dependence at horizontal scales from 70 to 700 km, while the vertical wave number spectra exhibited an approximately kz-2.7 dependence at vertical scales from 2 to 10 km. These spectra are compared with spectra obtained from ground-based lidar, radar, shuttle reentry, and Global Atmospheric Sampling Program observations. The rms horizontal wind velocity inferred from the airborne Na lidar data increased with time and with longitude from the Pacific Coast to the Great Plains. The inferred mean rms horizontal wind velocity was 32 m s-1, and the mean horizontal velocity variance was about 1100 m2 s-2. This horizontal velocity variance is comparable to horizontal velocity variance inferred from radar observations, but larger than horizontal velocity variances inferred from shuttle re-entry observations. During the round trip flight from Denver, Colorado, to Springfield, Illinois, two quasi-monochromatic waves were observed. The longer wavelength wave had an intrinsic zonal wavelength of 772 km, intrinsic zonal phase velocity of 35 m s-1 westward, and intrinsic period of 6.1 hours. This wave appears to be propagating almost due west. The shorter wavelength wave had an intrinsic zonal wavelength of 263 km, zonal phase velocity of 43 m s-1 westward, and period of 1.7 hours. ¿ American Geophysical Union 1990