The Transportation Security Administration's (TSA) Secure Flight program-established to identify those passengers who may pose security risks before boarding an aircraft-is a frontline defense against acts of terrorism that target the nation's civil aviation system. TSA developed and implemented Secure Flight in response to requirements in the Intelligence Reform and Terrorism Prevention Act of 2004 and a recommendation of the National Commission on Terrorist Attacks upon the United States (the 9/11 Commission) that TSA assume from air carriers the function of matching passengers against watchlists maintained by the federal government.