Comprising many airplanes, airports, aircrew, and employees, aviation industry is a large sector that is very vulnerable to attacks, whether it is from terrorists or criminals. Aviation history is fraught with examples of airport bombings, hijackings, and sabotage terrorist attacks. The most destructive of which is the tragedy of September 11, 2001, the cornerstone of today's aviation security policies. This study uses risk assessment tools to determine the dimensions of danger and threats against the aviation industry and addresses how vulnerable the aviation sector is. After vulnerabilities and threats are examined, possible impacts of attacks against the aviation security are discussed. This study also explores the pre and post September 11 policies that governments and policy makers develop to reduce risks in aviation sector. In addition, it discusses weaknesses and strengths of these policies which surfaced during the implementations. Finally, this study proposes some recommendations based on vulnerabilities and threats of aviation security.