Security measures Terrorism -- 8 Prevention 5 Aeronautics, Commercial -- 4 Prevention. -- 3 War on Terrorism, 2001-2009 3 Airports -- 2 more ... Evaluation. -- 2 Government policy -- 2 Hijacking of aircraft -- 2 National security -- 2 Security measures -- 2 Air power -- 1 Civil defense 1 Civil defense -- 1 Defenses 1 Freight and freightage -- 1 Harbors -- 1 Information warfare -- 1 Merchant marine -- 1 Military policy 1 National security 1 Passenger traffic 1 Politics and government -- 1 Surface-to-air missiles 1 Total quality management 1 Transportation -- 1 less ...