A look at airline security measures implemented after the Sept. 11 attacks.
Sept. 11, 2001 Hijacked aircraft are used to attack New York City’s World Trade Center and the Pentagon in Washington, D.C. Another hijacked plane crashes in Pennsylvania.
Nov. 19, 2001 President George W. Bush signs the Aviation and Transportation Security Act, giving the federal government direct responsibility for airport screening. The Transportation Security Administration is created to oversee security in all modes of travel.
Dec. 22, 2001 “Shoe bomber” Richard Reid is subdued by passengers and crew on a flight from Paris to Miami. This failed bombing prompts the TSA to require passengers to remove their shoes for screening.
Nov. 25, 2002 The Department of Homeland Security is established.
Dec. 17, 2004 Bush signs into law the Intelligence Reform and Terrorism Prevention Act. Among other measures, this law requires TSA to add butane lighters to its list of prohibited items.
March 31, 2005 TSA recognizes congressional intent and adds all common lighters to the prohibited items list. The U.S. becomes the only country to completely ban lighters from carry-ons.
Aug. 10, 2006 British officials uncover a plot to blow up aircraft using liquid explosives hidden in carry-on bags. In response, TSA bans all liquids, gels and aerosols from carry-ons.
Sept. 25, 2006 TSA announces that it’s modifying its ban on liquids, gels and aerosols and that passengers will be allowed to carry travel sizes of 3 ounces or less. These must fit into a 1-quart, clear, plastic zip-top bag. Passengers are also allowed to board with beverages bought in airports’ secure areas.
October 2007 In response to intelligence regarding terrorists using remote controls to detonate explosives, TSA begins conducting additional inspection of remote control devices like toys without banning them from carry-ons.
Dec. 25, 2009 Umar Faruk Abdulmutallab attempts to detonate an explosive device in his underwear onboard Northwest Flight 255. TSA works with the Department of Homeland Security, foreign partners and air carriers to swiftly implement enhanced aviation security measures.
April 2010 TSA puts new enhanced aviation security measures in effect for all carriers with international flights to the U.S.
October 2010 TSA implements immediate security measures for air cargo after suspicious devices made of modified printer cartridges are found onboard in-bound cargo aircraft.
November 2010 New pat-down procedures are introduced nationwide.
December 2010 Approximately 500 advanced-imaging-technology units are placed in airports in the U.S. The goal is to screen for harmful objects while avoiding physical contact.
On the horizon In February, TSA announced that it was testing new advanced-imaging-technology software to try to enhance passenger privacy. The new software will eliminate passenger-specific images and instead auto-detect potential threat items and indicate their location on a generic outline of a person.