I was in Atlanta with an outbound flight at the next gate that very day. Not only did the gate area quiet down but the concourse surrounding the gates did as well. Passengers respectfully lined the windows.
I have been on several flights during the conflicts with honor guards and flag draped coffins and the passengers have held their seats in silence. I have also been on flights with soldiers being recognized and applauded for keeping us safe at home.
I was also at LGA the evening we bombed Afghanistan and through the chaos of an airport in meltdown Delta got us home.
For all these little things Delta remains my airline of choice.