Danny,
I don't often disagree with you, but in this case you are so wrong. Even in Prison, where prisoners are repeatedly strip searched and constantly contained in a sterile envirnment it is impossible to keep the knives out with which prisoners are always murdering each other.
There is no accounting for a small group of people bent on suicide. Now that it has been proven just how easy it really is, this could be done by a group of unarmed people with martial arts skills.
The answer will be to configure the aircraft similar to the 757 PF, where the forward door is for the cockpit, and then there is a solid barrier between the main deck and the cockpit. Access to the cockpit is going to have be from outside the aircraft only, with its own self contained mini galley and Lav. In the case of the AA aircraft, they tried to storm the door and it held. THen they started cutting to flight attendants untill the pilots relented and opened the doors. The knives used consisted of plasic handles into which the razor blades from their shaving kit was inserted. More than enough to cut a throat.
The answer will have to be in a complete redesign of the aircraft to the above configuration, and in the short term armed sky marshals on every flight untill the aircraft is reconfigured. That way the crew can't be coerced into releasing the locks.
An aircraft is just a giant fuel air bomb. Turn on CNN if you don't believe me.
Wino