The reason that pocket knives were banned is that the 9/11 hijackers used box-cutters to forcibly open the flimsy cockpit doors. Nowadays, the cockpit doors of all US airplanes have been reinforced and are no longer vulnerable to this attack, so the need for banning pocket knives so longer exists. A simple solution would be to scrap the outdated ban on pocket knives.
my memory is that the box cutters were used as weapons to seize the plane, not to open doors. this is the first time i’ve ever even heard that and i suspect it isn’t true.
