Personally, I think George has it all wrong, and so do the three pilots quoted:

Armed (and Dangerous) Pilots (washingtonpost.com)

Prior to Sept. 11, if a passenger became unruly, the pilot might come back into the cabin to assert authority. No more. Says one of these three, "The flight attendants know they are on their own."

"You cannot fly an airplane and look over your shoulder, firing down the cabin," says one of these pilots. What you could do, he says, is look down the cabin by means of a closed-circuit television camera that would warn the flight deck of cabin disturbances requiring quick action to take the plane to the ground. Flight plans should show the nearest alternative airport at every stage of every flight.

Another potential problem with arming America's 120,000 commercial airline pilots is what one of the three pilots here calls, with no demurral from the other two, "cowboys or renegade pilots." Many commercial pilots began their flying careers as fighter pilots. Two of the three speaking here this day did. One of them says: There is some truth to the profile of fighter pilots as, well, live wires and risk-takers. Arming them might incite them to imprudent bravery. Armed pilots would be more inclined to go out into the cabin, whereas the primary goal should be getting the plane to the ground.

I think pilots should be armed, if for no other reason than it's another layer of defense. Lock the doors, yes. Install closed circuit TV so the flight crew knows what's going on with the passengers, yes. All fine, but I fail to see what's wrong with a last-ditch defense in the cockpit. This notion that pilots would have to "shoot over their shoulder while flying" is all wrong. Aren't there two pilots in the cockpit? That means one can fly while the other shoots if necessary.

As for "cowboy or renegade" pilots, those fighter jocks who now pilot commercial aircraft...I would think that those notions of being "live wires and risk-takers" would be suppressed merely by their being commercial pilots. They're not hot-dogging an F-15 through the sky, but a 767. It's not just them, it's 200+ civilians. That sense of responsibility should restrain them somewhat.

A good question is how El Al, Israel's airline, prevents hijackings. A USA Today article says that up to five armed guards ride on each flight, a far cry from a random, single "sky marshall" the US has. Israeli security opposes armed pilots, though, because they provide all these other levels of security, which is reasonable. We don't, however.

I don't expect El Al to publicly discuss all their security measures, but I do know that their security starts on the ground, where their passenger screeners do something strange and unique: They profile the passenger, not the luggage (link courtesy of Instapundit, thanks very much). Odd notion, one foreign to the United States, where we continue to focus on tools, rather than on the hand that wields the tool.