The No Fly List is a list, created and maintained by the United States government‘s Terrorist Screening Center (TSC),^[1] of people who are not permitted to board a commercialaircraft for travel in or out of the United States. The list has also been used to divert away from U.S. airspace aircraft not flying to or from the U.S.^[2] The number of people on the list rises and falls according to threat and intelligence reporting.^{[citation needed]} As of 2011, the list contained about 10,000 names.^[3][4] In 2012, the list more than doubled in size, to about 21,000 names.^[5] The list — along with the Secondary Security Screening Selection, which tags would-be passengers for extra inspection — was created after theSeptember 11 attacks in 2001.

The No Fly List is different from the Terrorist Watch List, a much longer list of people said to be suspected of some involvement with terrorism.^[6] The Terrorist Watch List contained around 1,000,000 names by March 2009.^[7][8]

The list has been criticized on civil liberties and due process grounds, due in part to the potential for ethnic, religious, economic, political, or racial profiling and discrimination. It has also raised concerns about privacy and government secrecy. Finally, it has been criticized as costly,^[9] prone to false positives,^[10] and easily defeated.^[11]

The No Fly List, the Selectee List and the Terrorist Watchlist were created by the administration of George W. Bush and retained by the administration of Barack Obama. U.S. Senate Intelligence Committee Chairwoman Dianne Feinstein (D-CA) said in May 2010: “The no-fly list itself is one of our best lines of defense.”^[12]