You're getting there. Although the tunnel system is far more organized and far more insidious than just airports. Denver Airport is a headquarters of sorts but the city under the Getty Museum far surpasses it. These tunnels don't just connect around the states but under the oceans and to other countries. The scary thing…they've been there much longer than people realize…and the true headquarters isn't even here.
Yes it's multilayered with horrific things going on down there. We'll know we've truly won once those kids are released.