Airglow imager and Na wind/temperature lidar measurements at Starfire Optical Range, New Mexico (35¿N, 107¿W) are used to estimate the seasonal variation of the vertical fluxes of horizontal momentum carried by high frequency Atmospheric Gravity Waves (AGWs). The cross-correlation coefficients between the vertical and horizontal wind perturbations were calculated from the OH airglow imager data collected during 32 nights in 1998, 1999 and 2000. The RMS wind velocities were deduced from the lidar measurements. The combined information was used to estimate the upper limit of the momentum flux. The meridional component of the vertical flux of horizontal momentum was observed to be towards the summer pole. The zonal component had westward preference in winter and weak preference in summer. The unanticipated large meridional component may act to regulate the summer to winter circulation in the mesosphere.