"Never again will a terrorist be able to breach the cockpit simply with a box cutter or a knife. The cockpit doors have been reinforced, and passengers, flight crews and air marshals would intervene."
Not true. Cockpit door opens when the captain takes a piss. Flight crews are usually sleeping at the back of the plane or stuck behind those beverage carts. Very few flights have air marshals and most passangers are tied up in their chairs with the seatbelt. I agree it is less likely than in the past, but definitely not impossible.
It would require split-second coordination among a group of terrorists sitting in the first few rows to take advantage of this before the crew becomes alert and closes the door. And even that opportunity is easily removed (if it isn't already) with a simple curtain preventing passengers from seeing the cockpit door.
In any case, 9/11 was only possible because passengers had been previously instructed to passively cooperate with hijackings. Before the end of that day, they were ready to fight to the death instead.
When I flew Southwest a couple weeks ago, a flight attendant specifically stood watch while the captain used the restroom, and had any passengers who walked up return to their seats.
I've also been seeing metal security curtains temporarily pulled across the aisle, so that the cockpit, the restroom, and the front kitchen are all behind a metal curtain, sort of like this:
I'm not sure how to answer that. The cockpit door was locked except for the brief moment when the pilot exited and re-entered the cockpit, and during that time a flight attendant was standing watch. I'm not sure how much more could be done, but it seemed to me it was a fairly significant obstacle to anyone hijacking the plane, considering that passengers would also hopefully assist in preventing a terrorist from succeeding.
Isn't it true that when Cockpit staff wish to leave a none Cockpit staff on the outside have to go up to the door and stand guard as they open the door?
On flights I've been on recently, they declared a fasten-seatbelts-and-stay-seated order in the cabin when one of the pilots stepped out to use the restroom. There was also a flight attendant standing guard outside.
Not true. Cockpit door opens when the captain takes a piss. Flight crews are usually sleeping at the back of the plane or stuck behind those beverage carts. Very few flights have air marshals and most passangers are tied up in their chairs with the seatbelt. I agree it is less likely than in the past, but definitely not impossible.