> After 9/11, unlock the pilot doors. The passengers will revolt against any attempted aircraft hijackings.

Regulations for locked cockpit doors were only introduced after 9/11, IIRC.

Do we need that? MH370 may have benefitted, but it’s hardly a common problem.

The belief is that MH370 was depressurized which would have killed the passengers. A better example is Germanwings 9525 where the locked door allowed the first officer to crash the plane.