Flight testing is often used as a final critical check of aerodynamic designs developed by computational and wind tunnel methods because the information obtainable in wind tunnels is subject to interference. Outdoor schlieren systems using the sun and moon make it possible to examine shock waves and other phenomena from aircraft in flight. Applications exist in all forms of research and development associated with turbulent flow fields, including aero optics, flow control, drag, boundary layer transition, and flow separation. The proposed developments will be extremely important in flight-testing, where few such instruments can perform in a flight environment. Potential commercial applications include aero-optics, flow diagnostics, flow-control, free-space laser communication, active laser imaging, high bandwidth video transmission, spectroscopy, and high-resolution imaging.