The evolution of the National Airspace System via the Next Generation Air Transportation System program depends on enabling new operational concepts to increase efficiency. Decreasing the spacing between aircraft on takeoff and landing would increase the throughput of airports. On-board sensing capability for wake vortices could allow aircraft to operate with reduced spacings. Wake vortices can be detected by a lidar located on the aircraft, but such a system needs to be small, lightweight, rugged, and require minimal maintenance. The Phase I program showed the feasibility of an intrinsically low-cost, coherent lidar that would be suitable for deployment on commercial airliners for axial wake vortex detection. The Low-Cost Lidar Test Bed was used to demonstrate measurement of aerosol returns. The program also assessed the feasibility of using the lidar for remote detection of clear air turbulence and volcanic ash clouds. The program developed a conceptual design for a prototype system that would be fabricated and ground tested in the Phase II program. The Phase II program will design and fabricate an engineering prototype compact coherent Doppler lidar and demonstrate it by measuring ambient wind fields at nearby venues.