heaven forbid some one look at somethinged with unbiased eyes... Even the NTSB said it was a waste of thier time and money, they only did do to offical requests from congress/white house. There were only a couple airlines that would even let thier pilots in the program, ( I want to say there was 3, but its been awhile) the rest said no.
The NTSB and the White house fought it every step of the way and kept it from being implemented for over a year.
It was the NTSB that came up with the brilliant policy of "lets make the pilot mess with it every time he takes off and lands, and Hey I've got another idea, lets have them put a PADLOCK through the triggerguard while he's trying to land the plane. Some ones sure to blow their nuts off that way"
Actually, hijackers have come up with methods of dealing with Air marshals. They have one or 2 wait a while in their seats, if the Air marshals intervene they shoot him in the back. As for armed pilots and locked doors, they are only psychological deterrents. You tell the pilot I'm going to kill 1 passenger every 2 minutes until you open the door, it'll open, if not theres always explosives. But PASSENGERS are unpredictable, there have been several cases where passengers have jumped hijackers since 9-11 and the hijacker is usually killed as in the "South West Airlines hijack attempt where the fat lady sat on the hijacker. He died of suffocation