I have been told by a well-informed person that, because the CDC is in Atlanta, that there is a mechanism designed to quickly isolate the city in case of biological emergency. One would assume that would include provision for a keystroke-operative shutdown of the airport . . . including isolation of communication hubs (cell towers and wifi). Note the mysterious "bridge fires" a few years ago, quickly isolating the city by road. Assume that was a test of the system.