I sincerely hope that somebody doesn’t think I am exposing any secrets. Each point below is obvious to anybody willing to spend five-minutes thought. I obviously have nothing to say about invisible procedures.
If we limit the amount of liquid that each passenger can carry on board to X ounces so that no person can carry enough explosive to blow up or blow a hole in an aircraft, and it takes Y ounces to do so (with Y > X), then all terrorists need to do is to buy N tickets, where N * X ≥ Y, with each of the N terrorists carrying his limit of the explosive, which can then be mixed together in the aircraft toilet. To say that terrorists limit themselves to no more than one per flight is to, at least, neglect history.
In any case, preventing a large conspiracy to smuggle explosives is difficult. For example, any passenger can buy a large container from an airport shop behind security, and can carry that container on board. Presumably, the invisible aspects of security minimize this threat (I speak from hope and not experience).
Having a gloved TSA agent check your boarding pass so that the printing on the boarding pass matches that of your identification is useless. It is trivially easy to create a false boarding pass. Or even easier to buy a genuine ticket in the name that matches the identification, just as the 9/11 murderers did.
It is useless to limit passengers’ movement in the cabin for the last hour of the trip (except for reasons of turbulence, landing, and so forth). It is just as useless to blank out the airplane tracking graphics available in some aircraft. Banning radios (receivers) is useless in the same way: I have tried to listen to FM radio while aloft, but have been told this is illegal. A trip to the toilet allows anybody to communicate with the ground undetected.
Removing toilet doors and replacing them with curtains, secured with a strap to indicate occupancy, would have minor use. This is not drastic as it sounds: airport toilets would become like any public restroom.
Banning blankets, pillows, and other objects that cover passengers’ laps is useless.
Metal detectors are useful, but imperfect and limited.
Patting down passengers before they can board can be useful, but it is not an exact procedure, especially with fat passengers. The usefulness of this procedure can be greatly enhanced if it is combined with profiling.
It has been suggested that passengers be allowed to carry firearms on board because terrorists won’t strike when they fear other passengers might be armed. This is obviously silly. A gun needed only be used to threaten or take another’s life: it can also be used to poke holes in mechanical objects.
What would be useful, and expensive, is to install obviously (and properly) armed security guards on each flight. Airlines that take this step could boast of this. President Obama ended the program the allowed trained pilots to carry guns.
Most useful would be to extend profiling in combination with traditional procedures. Obviously, some profiling is already conducted; no-fly and watch lists exist, for example. Profiling at the security check point has some use, but it is limited: e.g., TSA guards could more assiduously search certain passengers. Better would be to beef up the behind-the-scenes profiling where passenger’s names are checked when the ticket is issued.
I do not say that the TSA should be given more power. Their mandate should be narrowed, and limited solely to making individual flights (or trains, etc.) safe. They should not be given powers that are already in the hands of the FBI and other law enforcement agencies. Once a passenger has been determined to be free of weapons, explosives, and so forth their authority should stop absolutely.
What happened to reporter and American citizen Michael Yon should not be allowed. Among other things, the TSA agents asked the handcuffed Yon, “How much money do you make?” Any citizen should be allowed to say, “None of your damn business”, or even refuse to answer. This question is irrelevant to the safety of an individual flight.
What’s most interesting about this is the response from Senator Frank Lautenberg (D). He was careful to be quoted as saying, “This system was broken.”