Optical techniques are increasingly being used to measure the dynamics and influences of gravity waves in the mesosphere and lower thermosphere because of their unique spatial sensitivity and their potential for high-resolution measurements of winds and temperatures at these altitudes. Such systems, however, also exhibit measurement biases which can, if uncorrected, cause significant errors in inferences of dynamical quantities. Inappropriate assumptions about the character of the motion field can likewise lead to errors in data analyses. Estimates of momentum and heat fluxes due to gravity waves are particularly sensitive to such errors because of their dependence on correlations among wave quantities and the character of the wave motions. The purpose of this paper is to identify such errors in previous applications of lidar and airglow data collected at the Starfire Optical Range and in Hawaii in order that subsequent data analyses will yield useful estimates of gravity wave fluxes, mean flow influences, and guidance for modeling studies in the future. ¿ 2000 American Geophysical Union