Over the years, the volume of air traffic has increased significantly. The number of kilometers traveled in air transport is increasing, the number of carried passengers is increasing, as is the air freight traffic is increasing. Today's aviation development relates to many areas, such as infrastructure, human resources, crew trainings and connecting places. The key objective of these development efforts is to ensure the safe and efficient transportation of people and freight. In the last decades, we can see great progress in aviation safety. Despite the good prognosis for further improvement of aviation security, there are still some certain risks and aviation accidents, which are mainly the result of a different approach to compliance with aviation safety criteria, aviation regulations and international aviation standards. All air accidents are subject to thorough scrutiny. The circumstances of these accidents are identified through a comprehensive and demanding investigation aimed at preventing the recurrence of such incidents or accidents in the future, and thus maintaining and improving confidence in aviation. The diploma thesis deals with the factors of aviation safety, aviation accident investigation and its impact on aviation safety which are analyzed in more detail.