Did you suspect the blonde air crew lady...
... might have been part of the terrorist group?
Although I had seen this film several times since the '80s, it had been a long time for me before last night, and I kept thinking she was going to be handed a gun and surprise everyone by revealing her true role.
Just the way the character felt and the possibly-dyed light blond hair. The cockpit door scene seemed like the possible reveal but of course, it didn't happen.
On another note, I found that cockpit door kind of amusing, how the door is opened quickly and slams the terrorist in the face, and knocks the grenade pin from his hand. Oops...