This literature review finds that the main malicious threats to civilian aviation since 1975 are attacks by terrorist groups, deliberate or accidental damage arising from conflicts, and incidents caused by people who work for airlines or airports. While the sector has responded to hijackings and bombings with increasing security since the 1970s, actors seeking to attack aircraft have modified their tactics, and new threats such as liquid explosives and cyber attacks have emerged. Civilian aviation has seen relatively fewer accidents and deaths over the years, but threats remain. The review focuses on malicious threats to civilian aviation. It, therefore, excludes weather events or accidents. The first section lists major malicious threats to civilian aviation since 1975. It includes both actual and planned events (e.g. hijackings that were prevented) that are recorded in open-source documents. Each threat is listed alongside information on its cause (e.g. terrorism, state actions, crime), the context in which it occurred (broader factors shaping the risk including geography, regime type, technology), and its impact (on passengers, policy, security, economic). The second section discusses some of the trends in threats to aviation. Motives for malicious threats include terrorism, crime, asylum-seeking, and insider attacks by aggrieved or mentally ill airline staff. Hijacking has been the most common form of threat, although bombing or suicide attacks have killed more people. Threats may also take the form of accidental attacks on civilian planes misidentified as threats in conflict zones. Experts suggest that growing threats are cyberattacks and the use of unmanned aerial vehicles, although neither has yet caused a major incident.