Aviation security has becomingly increasingly technological in focus over the past decade or so. New advances in spectrometry and biometrics have made the process of screening passengers and baggage more effective than ever before - even as the field has gained unprecedented relevance in the public eye.

Due to the large volumes of people who pass through airports, and the frequently international nature of their travel, airports have always presented particular problems for security. Even before the more modern threats of terrorism, aviation presented opportunities for crimes such as drug trafficking or flight from justice.

Today though, airport and air travel security processes are designed to screen for a range of possible elements. Many items are banned for passengers, often in response to past incidents where they have been used to hijack or destroy the plane. In response, aviation security uses a variety of screening devices in addition to the sniffer dog teams traditionally used to detect narcotics and contraband.

These devices include metal detectors, which effectively eliminate the most common items that could be used as improvised weapons or in an explosive device. Obviously, metal detectors can prove unsuitable for baggage and luggage; instead, more thorough screening is usually achieved using X-ray machines and/or chromatography machines. This latter equipment can detect the volatile compounds given off by explosive devices, whilst the former can non-invasively examine objects and baggage.

However these systems must be deployed consistently to be effective. Most airports used a similar basic model for their routine security, based upon the screening of the public into the secure areas reserved for civil and international aviation - often referred to as "sterile" or "airside". Once checked in and through security, passengers are re-screened each time they leave and return to the 'airside' areas. Beyond the terminal area, the exit gates are generally separated by additional layers of lighter security whilst the public are restricted at all times to non-sensitive areas. In many cases embarking and disembarking passengers from separate flights will be kept separate by barriers and security checkpoints.

Of course other innovations have proven a massive help to aviation security. Intrusion detection systems, remote alarms, CCTV systems and communications systems all play vital roles in the policing of the busy environments of aviation. Providing real-time updates for detection and location of security threats, they help monitor potential situations and direct personnel effectively.