Airport security changed radically after Sept. 11, 2001. Before the terrorist attacks, private companies provided airport screening services. These companies worked under the guidance of the U.S. Federal Aviation Administration, and although their representatives scanned passengers using metal detectives and X-rayed bags, limited federal security requirements existed for cargo and baggage screening. After 9/11, the U.S. government established the Transportation Security Administration to improve and strengthen aviation security. By November 2001, the TSA was rolling out a number of new security measures: armed air marshals, reinforced cockpit doors and no-fly lists identifying people who could pose a threat and designating them for enhanced screening or, as appropriate, prohibiting them from boarding an aircraft.
Today, the TSA screens 100 percent of checked baggage for explosives. Most airports integrate this screening process into their baggage claim solutions. Using combinations of software, conveyance systems and screening technologies -- computer tomography, X-ray machines and explosive trace detection -- airports can now conduct full in-line screening without interrupting or delaying the movement of luggage from the ticket counter to the aircraft.
The TSA also subjects passengers to much more rigorous screening procedures that can involve pat-downs and whole-body scans. The latter involves so-called advanced imaging technology machines, which have been installed at some 200 airports since 2008 [source: TSA]. The machines come in two flavors, based on the type of electromagnetic radiation they use to make a scan. Backscatter machines send low-energy X-rays to bounce off a passenger's body. Millimeter wave (mmv) scanners emit energy more akin to microwaves. Both see through clothing to produce a 3-D image of the person standing in the machine, revealing any threats he or she may be trying to conceal. In either machine, the scanning process is the same. Passengers must remove everything from their pockets, as well as belts, jewelry, lanyards and cell phones. Then they step up a small ramp and, stand in the center of the machine, raise their arms, bent at the elbows, and remain motionless as the device completes a scan. For backscatter machines, the process takes about 30 seconds. For mmv scanners, it takes about 10 seconds.
Airports have also increased their on-site police forces since 9/11. At Los Angeles International Airport, for example, the police crew has grown from 100 sworn officers before the terrorist attacks to 430 today. This makes the airport force almost as large as others performing their duties out on the city streets [source: McCartney]. Some airport police are members of the city or municipality assigned to the airport, while others are from private security companies. Either way, their highest priority is thwarting a threat to a plane or to the airport itself. They question people who are photographing aircraft, conduct random searches of cars to turn up illegal guns and drugs, monitor traffic on the tarmac and around the terminals and investigate reports of theft at security inspection points. Many airports also use bomb-sniffing dogs to check out unattended bags, garbage cans and vehicles.
Airports complement their police forces with separate crews to handle fire and emergency medical services (EMS). An airport may have several fire/EMS stations on the ground because the FAA requires that emergency crews be able to reach the midpoint of a runway within 3 to 5 minutes. The crews are usually employees of the city or municipality and are stationed at the airport. At their disposal are specially designed and equipped fire and rescue vehicles capable of extinguishing jet-fuel fires with thousands of gallons of foam. These 44-ton, six-wheel vehicles can accelerate from 0 to 50 miles per hour in less than 35 seconds and come equipped with a variety of turrets, nozzles and booms to attack a fire efficiently and protect escaping passengers [source: Rosenblum].