but not allowed once airborne.
What is the problem with the captain going down the back and showing command responsibility rather than cower behind the terrorist proof door and pretend it will all go away. Thre is a wealth of difference between the captains of the past and the wimps in the left seat now. I recall one captain from 25 years ago who shirt-fronted a bunch of rowdy footballers at Port Vila when he saw them walking towards his aircraft. He left his seat and charged down the stairs and held up his hand and read the riot act to them while the other passengers boarded. He then permitted the foot ballers to enter the aircraft and there was no trouble during the flight.
I realise that after 9/11 the aviation world changed. But noisy school kids? surely they weren't too much of a threat.