Unmanned aircraft systems (UAS) is a general and complete term which includes aircraft as well as supporting ground, air, and communications infrastructure. UAS come in a variety of shapes and sizes and are viable for a broad range of civilian, commercial, and military applications. Current domestic use of UAS is limited to academic institutions, federal, state, and local government organizations that receive a Certificate of Waiver or Authorization (COA) and private sector entities that receive special airworthiness certificates by the FAA, and hobbyists who may only operate under tight restrictions. Typical domestic applications of UAS include border patrol, scientific research, and environmental monitoring. For example, NASA has made extensive use of a myriad of advanced UAS to conduct aeronautics, meteorological, and environmental research over the years. Though military and civil government will likely dominate large UAS operations in the near term, the UAS market is dynamic and the commercial sector is poised for significant growth, particularly in the small UAS sector. The Teal Group, an aerospace and defense industry market intelligence firm, forecasts worldwide annual spending on UAS research, development, testing, and evaluation (RDT&E) activities and procurement rising from $6.4 billion in 2014 to $11.5 billion in 2024.