( CNN ) -- As a federal air marshal , Robert MacLean typically spent five days a week crisscrossing the country on commercial flights , reading a lot of newspapers and John Grisham novels while keeping an eye out and trying to appear inconspicuous . `` It was a well-paying job with enormous responsibility , yet extremely tedious and mundane , '' he said . `` You did the same thing every day , there was nothing new . You sat in your seat and prayed that nobody would set off an IED or ambush you mid-flight . '' Armed with service weapons and usually traveling in pairs , federal air marshals are tasked with detecting , deterring and defeating `` hostile acts targeting U.S. air carriers , airports , passengers , and crews , '' according to the Transportation Security Administration 's Web site . If the air marshals are doing their job properly , the public does not learn about the incidents or potential catastrophes they 've prevented , Department of Homeland Security spokesman Nelson Minerly said . `` Federal air marshals are trained to operate covertly and to blend in with the traveling public , '' he said . `` They work in the air and on the ground as a last line of defense , but if they 're doing the job right , you do n't know they 're there . '' A federal air marshal was not on Northwest Flight 253 when a passenger allegedly tried to detonate explosives hidden in his underwear . But the agency said the incident prompted it to enhance airport screening procedures and put more air marshals aboard flights . The Federal Air Marshal Program has been around in one form or another since the early 1960s , when a rash of hijackings of flights to Cuba prompted President Kennedy to order that federal law enforcement officers be placed on high-risk flights . The Federal Air Marshal Service officially began in 1968 as the Federal Aviation Administration 's Sky Marshal Program , and in the 1970s , extortion-type hijackings in the Middle East led to the deployment of some air marshals overseas . In 1985 , President Regan expanded the program , increasing the number of air marshals , in response to a series of domestic and international hijackings , including TWA Flight 847 , in which a U.S. Navy Diver was killed and his body dumped on the tarmac in Beirut , Lebanon . The terror attacks of September 11 , 2001 , represented a turning point in the agency 's history , when it grew from less than 50 officers to the several thousand currently employed as federal law enforcement officers in the TSA , Minerly said . Law enforcement officers and military personnel made up most of the first recruits to join the agency 's replenished ranks in October 2001 , said Jamie Smith , a former federal air marshal instructor and current CEO of SCG International , a global security firm . Recruits are trained extensively in tactical operations and law enforcement procedure . `` They go through how to go hands-on with somebody in the tight confines of an aircraft , from how to disable an attacker from a seated position , how to fight if you fall down in the aisle , or how to use different items onboard to subdue and restrain attackers , '' he said . `` They learn how to restrain them using seatbelts -- basically fold the person over and strap them down . '' Trainees also learn the rules of engagement , laws related to use of force on airplanes and how to look out for suspicious behavior , or behavioral profiling . `` We 'd teach them to look for mannerisms : specific styles of dress , whether they 're with a group or trying to peel off from a group , or if a uniformed officer approaches and they shy away -- things like that . We 'd teach them what to look for , '' he said . Applicants with backgrounds in law enforcement and the military are given special preference , but the positions are open to anyone with a college degree or three years of professional experience who proves up to the job , Minerly said . `` Our training program is very comprehensive . We have people applying now with limited law enforcement experience and we provide them with the training to get them up to speed with what we expect of a federal air marshal , '' he said . `` Air Marshals are supposed to look like the rest of the traveling public so it only stands to reason we would want recruits from all walks of life . '' In the eight years since the Federal Air Marshal Service has been ramping up , only a handful of incidents have been publicly reported , most involving drunk or unruly passengers . MacLean says he never had to make an arrest in five years flying missions as an air marshal . Yet his career ended in controversy , when he was fired for leaking information on cutbacks in the program . Did he ever secretly wish for some action to break up the tedium ? `` No way , '' he said , laughing . `` Not when you 're 35,000 feet up in the air flying at 500 mph in an aluminum tube with a few hundred people . You really do n't want anything to happen . ''
Federal air marshals spend a lot of time on commercial flights reading , staying inconspicuous . If they 're doing their job right , passengers should not notice air marshals aboard flight . Concept of air marshals originates in early 1960s , when rash of flights to Cuba hijacked . Background in law enforcement not required but preferred .