[mrguyorama]

>It’s because we learned to pre-empt coordinated well organized attacks using intelligence, and we hardened physical security at the cockpit door (I’m guessing mostly the latter).

You're forgetting the REAL reason airplanes are basically not hijacked anymore: Flight 93.

It used to be, if you threatened to blow up an airplane, the passengers would largely choose not to confront them, because the SOP of hijacking was to land somewhere and negotiate. Indeed this desire to not rock the boat actually turned one hijacking by drunk teens into a catastrophe when the hijackers were too stupid to understand that a plane couldn't just fly to Australia without picking up more fuel, Ethiopian Airlines Flight 961.

9/11 changed that risk calculus for passengers. Now everybody knows what hijackers COULD do, and are willing to endure some danger to prevent that, to the point we've kind of overcorrected and people are yelling at and harassing fellow passengers for non-issues.