The National Test Pilot School (NTPS) began offering an Unmanned Aerial Vehicle (UAV) flight test short course in April of 2006. Initially, various flight test techniques were taught solely through simulation. To improve the quality of training provided, it was necessary for NTPS to acquire an Unmanned Aircraft System (UAS). With few exceptions, UASs cannot currently be operated in the NAS and are platforms that require extensive training for safe operation. Consequently, a Cessna 150 was converted into an Optionally Piloted Aircraft (OPA). It is currently intended that the OPA will always have a certified airplane pilot on-board who can deactivate the ground-controlled autopilot system at any moment. The system is capable of being to be controlled via command direction or in a remotely piloted vehicle mode. The aircraft was certified in August of 2010 as an Optionally Piloted Aircraft by the FAA. This paper outlines the development, certification, ground and flight test process that was completed for this OPA. This paper will include a description of the development, evaluation, and validation of flight test techniques using the OPA as a surrogate for UASs. NTPS has found that OPAs are an essential evolutionary step from flight testing manned aircraft to UASs.