The Department of Homeland Security has indicated that terrorists are still seeking ways to attack the United States through the aviation sector, applying the strategy of September 11 to attack chemical plants, petroleum and petrochemical facilities, transportation systems and facilities, and electric power grids. Insufficient security systems in the aviation industry and the sensitivity of aircraft to attacks continue to make the aviation sector an attractive target for terrorists. Security measures are not limited only to the inside of the airports and the airplanes. Other points of security vulnerability are perimeter systems, hangars, office buildings, gas stations near airports, and the accessibility of the airports. Because air cargo shipments will continue to grow significantly within the next 10 years, these airplanes and their facilities are also at risk for terrorist hijackings and attacks. Further, the lack of standardization in security measures and responding to the risks also increases vulnerability, as terrorists continue to probe for weaknesses at international airports throughout the world. This suggests that aviation security should be managed cooperatively, not just by individual countries. Although many international conventions deal with aviation security, and many regulations have been developed, there is no comprehensive and effective international aviation security system. Other vulnerabilities are the lack of intelligence sharing and cooperation, the threat of shoulder-launched surface-to-air missiles, and aviation computer systems. The impact of terrorists’ attacks against aviation are discussed under two areas: the psychological impact as people’s anxiety, fear, mistrust, resentment, and reactions increase in disproportion to the actual threat; and the economic impact on the aviation industry. 41 references