The thing I notice that I think is so ridiculous is how thin and weak the flight-deck doors are. They look like they can be opened with a fist. What they need are much stronger doors, maybe even made with titanium or steel. The knobs on the flight-deck doors are pathetic as well. A hijacker can just shoot the knob and open the door. Solution: Bulletproof doors. The pilots should be the safest people on the plane. As much as I love to peer into open flight-deck doors from my seat, I would readily give that up for a safer flying environment. Heres what it should be like. The flight crew gets in the plane, closes the door, and locks it. The door should be bullet proof. No way anyone can enter without a code, which only the crew and special ground staff know. If flight attendents have the code or key, they can be forced into giving it to any hijackers. Only in this way can the pilots be safe, and the passengers.
The aircraft frame should be reinforced, to handle certain gunshots without causing the plane to explode or bust a hole. This way, there can be an armed marshal on board without the risk of his gun blasting the plane out of the sky. But lets first start with the basics. Strengthen the damn cockpit doors for god sakes, they are so weak. Just my two cents