The No Fly List, maintained by the United States federal government's Terrorist Screening Center (TSC), is one of several lists included in algorithmic rulesets used by government agencies and airlines to decide who to allow to board airline flights. The TSC's No Fly List is a list of people who are prohibited from boarding commercial aircraft for travel within, into, or out of the United States. This list has also been used to divert aircraft away from U.S. airspace that do not have start- or end-point destinations within the United States. The number of people on the list rises and falls according to threat and intelligence reporting. There were reportedly 16,000 names on the list in 2011, in 2012, and in 2013. The list—along with the Secondary Security Screening Selection, which tags would-be passengers for extra inspection—was created after the September 11 attacks of 2001. The No Fly List, the Selectee List, and the Terrorist Watch List were created by George W. Bush's administration and have continued through the administrations of Barack Obama, Donald Trump and Joe Biden. Former U.S. Senate Intelligence Committee chair Dianne Feinstein said in May 2010: "The no-fly list itself is one of our best lines of defense." However, the list has been criticized on civil liberties and due process grounds, due in part to its potential for ethnic, religious, economic, political, or racial profiling and discrimination. It has raised concerns about privacy and government secrecy and has been criticized as prone to false positives. 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. As of June 2016, the Terrorist Watch List is estimated to contain over 2,484,442 records, consisting of 1,877,133 individual identities. History Before the attacks of September 11, 2001, the U.S. federal government had a list of 16 people deemed "no transport" because they "presented a specific known or suspected threat to aviation." The list grew in the immediate aftermath of the September 11 attacks, reaching more than 400 names by November 2001, when responsibility for keeping it was transferred to the Federal Aviation Administration (FAA). In mid-December 2001, two lists were created: the "No Fly List" of 594 people to be denied air transport, and the "Selectee" list of 365 people who were to be more carefully searched at airports. By 2002, the two lists