Radar is valued for its ability to surveil large areas, day and night, in all weather conditions, with high revisit in order to provide detection and tracking of individuals and groups. Such radars operate either stand-alone or while networked and may generate cues for EO/IR sensors for identification and classification. In the security applications domain radar basing or siting has been predominately, if not exclusively, from fixed, ground-based positions (this includes mobile systems that must be stationary when employed). Airborne radar systems employing phased array antennas and advanced adaptive processing are investigated for their ability to detect and track individuals, in a security application, when integrated with small and medium unmanned air vehicles. Airborne surveillance radar overcomes many of the visibility issues of ground-based systems by operating at steeper grazing angles. We evaluate performance for two operating altitudes and in a variety of surface wind conditions, demonstrating high probability of detection against walking human targets. These results suggest the viability of UAV-based airborne radar as candidates for future surveillance architectures.