There was a post (I believe here on HN) several years ago about a guy who made improvised weapons in airports using only things that were available in Duty Free aka after you had gone through security.
He had all kinds of things: stun guns, flamethrower, club etc.
The details are kind of secondary to a point someone made in the comments:
"This guy has clearly demonstrated that it's trivial to do all of the things necessary to build these things and take over an airplane. The fact that no one has done so in the past couple years has made me seriously question if:
a. anyone is trying (probably not)
b. given (a), do we really need all of this security theater?"
Honestly, between a) armored cockpit doors and b) the knowledge (both passengers, and pilots) of what happens if you let hijackers into the cockpit, a 9/11 style attack isn't likely to ever happen again.
Trabal knowledge gets forgotten too, just over longer timespans. One day, planes will fly with no one on board having been alive when 9/11 happened. They may not make the same assumptions about intent as adults today do. "Ever" again is a little long to be so sure.
"Tribal knowledge" of airplane hijackings was why 9/11 worked initially.
People sat still because a "standard" airplane hijacking meant going to some odd airport while a bunch of "freedom fighters" got their 15 minutes of fame and then everybody on the plane got safely released a week or two later.
Once people realized that the 9/11 hijackings instead were suicide runs, the "tribal knowledge" broke and people didn't sit still anymore (see: the fourth plane on 9/11 or the shoe bomber).
He had all kinds of things: stun guns, flamethrower, club etc.
The details are kind of secondary to a point someone made in the comments:
"This guy has clearly demonstrated that it's trivial to do all of the things necessary to build these things and take over an airplane. The fact that no one has done so in the past couple years has made me seriously question if:
a. anyone is trying (probably not)
b. given (a), do we really need all of this security theater?"
The original post reminds me of the above.