One of the most visible counter-terrorism efforts in the United States has been the increased airline security. Airline travelers complain of the increased scrutiny, and delays,  caused by Congressional unwillingness to allow profiling (meaning that Middle Eastern passengers would get more scrutiny, while elderly passengers of European ancestry would not.) Israel has used profiling for decades, and has had no terrorism problems (the terrorists dont even bother to try any more.) While the government security managers wont allow profiling, this doesnt stop airline passengers from doing so. Its widely understood that, if any terrorists attempted another September 11, 2001 type hijacking, they would quickly be confronted by a plane full of angry and violent passengers. But government airline security policy believes that  thousands of air marshals would deal with this sort of thing. This wont work for several reasons. First, there arent enough air marshals. The force was expanded from 32, before September 11, 2001, to several thousand today (the exact number is classified). While many are retired military and police, most have not received the specialized training required to make them more effective than dozens of enraged passengers. Moreover, the Air Marshal Service demands that marshals dress up (jacket and tie, and leather shoes and good grooming.) Hardly anyone dresses like that will flying any more. Its become something of a game with many frequent flyers to spot the marshal. You can often tell who the marshal is by looking for the best dressed, and most bored looking, guy on the flight. Air Marshals go several hundred flights without anything happening, and no terrorists have been captured yet, much less terrorism attempts thwarted. Despite the easy work, many marshals are quitting in disgust. But those looking for an easy job, with no hassles, have found the Air Marshal Service a nice place to be. And because of their dress regulations, passengers have no problem finding a marshal if they need one.