CRS report – Transportation Security: Issues for the 114th Congress. Bart Elias, Specialist in Aviation Policy; David Randall Peterman, Analyst in Transportation Policy; John Frittelli, Specialist in Transportation Policy. May 9, 2016.

“The nation’s air, land, and marine transportation systems are designed for accessibility and efficiency, two characteristics that make them highly vulnerable to terrorist attack. While hardening the transportation sector from terrorist attack is difficult, measures can be taken to deter terrorists. The dilemma facing Congress is how best to construct and finance a system of deterrence, protection, and response that effectively reduces the possibility and consequences of another terrorist attack without unduly interfering with travel, commerce, and civil liberties. Aviation security has been a major focus of transportation security policy since the terrorist attacks of September 11, 2001. In the aftermath of these attacks, the 107th Congress moved quickly to pass the Aviation and Transportation Security Act (ATSA; P.L. 107-71) creating the Transportation Security Administration (TSA) and mandating a federalized workforce of security screeners to inspect airline passengers and their baggage. Recent events, such as the destruction of a Russian passenger jet above the Sinai Peninsula on October 31, 2015, apparently by a bomb aboard the aircraft, have renewed concerns about the adequacy of passenger and cargo screening. Similarly, bombings in Brussels, Belgium, on March 22, 2016, renewed concerns over the security vulnerabilities of airport terminals and mass transit stations…”