Aviation security refers to the tactics, techniques and procedures applied in protecting airports and by extension aircraft from crime and terrorism. Large numbers of people pass through airports every day. Such a large gathering of people presents a natural target for terrorism and other forms of crime due to the number of people located in a small area. Similarly, the high concentration of people on larger airliners and the potentially high lethality rate of attacks on aircraft provide an alluring target for terrorism.

Aviation security provides a first line of defense by attempting to stop would-be attackers from bringing weapons or bombs into the airport. If they can succeed in this, then the chances of these devices getting on to aircraft are greatly reduced. As such, aviation security serves two purposes:

1. To protect the airport from attacks and crime
2. To protect the aircraft from attack