Pre-9/11, the expectation was you don't draw attention to yourself, wait it out, you're going to have a long day and a story to tell. Post-9/11, the expectation is you fight for your life.
Better cockpit doors and access hygiene probably come second.
"Post-9/11" began minutes after the first planes found their targets. Flight 93—the one that crashed in Pennsylvania—never made it because the passengers revolted after hearing about the other planes.
It only took a few minutes for the calculus to change. Knowing what was up, those passengers flipped from wait-and-see mode to fuck-you mode. This is pretty good evidence that you're right: the biggest increase in security was and still is that passengers will not be meek anymore.
This recent video by RealLifeLore drives it home: https://www.youtube.com/watch?v=550EdfxN868&t=1504s
the last time in history that Sovereign American territory was invaded and occupied by a
hostile foreign power was between 1942 and 1943 when the Japanese occupied the
small and sparsely populated Alaskan islands of ATU and Kisa which they struggled to reinforce with supplies and
were only able to hold on to for a year before getting overrun by much better supplied American and Canadian soldiers
Later in the video: https://youtu.be/550EdfxN868?si=gpTplY4Z36tJPxLv&t=2706
that doesn't mean that the US cannot be hurt or have its interests disrupted in other ways the US Mainland
can obviously still become the subject of major attacks from hostile foreign powers if not outright invasions and the
biggest and worst attack that ever befell the US on its own territory happened recently only 23 years agoNot especially accurate. The US and Canadian forces that landed on Kiska had no opposition because the Japanese had already left. They did not overrun Japanese forces that were not there.
Wikipedia describes this as: "On 15 August 1943, 1st SSF was part of the invasion force of the island of Kiska, but after discovering that the island had been recently evacuated by Japanese forces, it re-embarked ..."
And yet, there were still friendly fire casualties, a point omitted from many descriptions of the invasion.
I’m pretty sure there is a second code on some planes that alerts the pilots someone is attempting to force the crew to open the door.
I have never heard of a plain clothes non-employee in cockpict jumpseat.
One of the more reasonable theories for MH370 is similar to the Germanwings case. Pilots can refuse access even if the person outside knows the access codes for the cockpit doors.
Unfortunately (as with everything else), even obvious improvements have potential downsides.
[1]: https://en.m.wikipedia.org/wiki/Helios_Airways_Flight_522 [2]: https://www.youtube.com/watch?v=YaOvtL6qYpc
That's why I said "If the CA had entered earlier".
While that may be a factor, there's never any news about this happening, except maybe shortly after 9/11 with shoe or underwear bombs.
Hijackings used to be common, they're not anymore post 9/11. There were 27 hijackings in 2000 worldwide. There were none in 2017, 1 in 2018, etc.