Some on those planes that crashed into the World Trade Towers did not know they were on a suicide mission. If you recall, Bin Laden chortled over that one. Thus, they could not be courageous. They were merely duped. As for the 'pilots,' they were deluded into thinking theirs was a noble cause and that they would reap a personal reward in their suicide.
I agree. I also don't see the courage in pulling a knife on unsuspecting and unarmed travelers (including women and children), lulling them into temporary compliance with lies about their future safety, and then crashing the plane. Absolutely absurd. Jere Longman's book "Among the Heroes" goes into some detail about the contents of the Flight 93 cockpit reporter tapes and how they demonstrate that those terrorists locked themselves into the cockpit and hid from the passengers. Courage my ass.