These were the first combatant causalities of the war on terror. Let's not forget, that there were also members from other countries on that flight that gave their lives to save others. They heard what was going on in NYC and DC, they knew what was planned for their plane, and they acted. They had to have known that they would not survive, but they still charged to cock pit to stop the terrorist from furthering the carnage.
May their memorial forever stand, and their sacrifice and their names never be forgotten. God Bless them and give them and their families peace.