SFO was one of several US airports that operated the Registered Traveler program from April 2007 until funding ended in June 2009. This program let travelers who had paid for pre-screening pass through security checkpoints quickly. Baggage and passenger screening is operated by Covenant Aviation Security, a Transportation Security Administration contractor, nicknamed "Team SFO". SFO was the first airport in the United States to integrate in-line baggage screening into its baggage handling system and has been a model for other airports since the September 11 attacks in 2001.