Aviation security refers to measures taken to keep aircraft and their passengers and crew safe. Aviation security has existed throughout most of the history of aviation. But various events throughout history have led to heightened security for those traveling on board aircraft. During the 1970s, modern airport security was first introduced. Following the September 11, 2001 attacks in the United States, security was heightened worldwide. A ban on carrying liquids was introduced in 2006. Over the years, experts have tried best to determine the best ways to conduct security of air travel, and what items to permit and ban.
Each commercial airport contains a sterile area where passengers must be screened prior to entry. The screening process includes examination of the passengers and their carry-on luggage. Luggage is generally x-rayed as it passes along a conveyor belt. Passengers have traditionally passed through a metal detector, though in recent years, airports in some places x-ray passengers with a millimeter wave scanner. Those who cannot be accurately examined with these devices may be subject to a patdown.
In all countries, it is forbidden to carry various items onto the cabin of an aircraft that are believed to have the potential to do harm to passengers and crew. The restrictions vary by country, but some items are universally banned. In addition, some items are also banned in checked luggage.
Commonly banned items include, but are not limited to: