Introduction
The national airspace security mission objective is to prevent or counter attacks on air vehicles, including attempts to use aircraft as weapons. Assessing risk, detecting and communicating threats, identifying and implementing mitigation strategies, executing joint responses, and recovering from security incidents are the key actions of airspace security. Execution of the mission requires coordination and collaboration by both civil and military government agencies as well as the private sector, with tightly choreographed activities from a number of independent organizations in multiple locations. The most prominent government stakeholders are the Department of Transportation's Federal Aviation Administration (FAA), multiple agencies within the Department of Homeland Security (for example, Customs and Border Protection and the Transportation Security Administration), and multiple branches of the Department of Defense (for example, North American Aerospace Defense Eastern and Western Air Defense Sectors). Airspace users (flight operators and crew) are the main private sector stakeholders. Also involved are local, state, and federal law enforcement and emergency responders.