During the most recent rounds of Base Closure and Realignment Commission activities in 2005, a significant number of training bases were closed. In light of the introduction of new technologies and the great expansion of unmanned aircraft systems (UASs) in the force, Department of Defense planners and some in Congress have become concerned that the existing training infrastructure bases and their training support facilities may not be adequate to train UAS air and ground components and the ground forces that use such equipment to capitalize fully on their capabilities. Accordingly, the Deputy Director, Readiness and Training Policy and Programs in the Office of the Under Secretary of Defense for Personnel and Readiness (OUSD [P&R]) asked the RAND Corporation to assess the adequacy of UAS training to support current and future requirements. In addition, the House Armed Services Committee report accompanying the Fiscal Year 2013 National Defense Appropriations Act raised a number of questions concerning training strategies with particular reference to the use of simulators to facilitate training.1 This report considers three issues: (1) the development of a general concept for UAS training in the context of current and anticipated future UAS inventories, (2) the development of an appropriate framework based on the general concept to address UAS training requirements, including the appropriate use of simulators, and (3) the airspace requirements necessary for UAS training. The research reported on here covers UASs in the Army, Navy, Air Force, and Marine Corps as fielded and plans as they existed during 2012. A RAND team carried out extensive field visits to understand the current ability of the services to conduct (1) service- specific training and (2) joint training at both home station and joint training facilities.