Dead Air

Dead Air is a campaign. The Survivors must make their way to a runway in hope of catching a plane away from the Infected.

Official description
Guide your team of Survivors out of the downtown core of Newburg's business district, through derelict office floors and still-inhabited cubicles, and out onto the runway of Metro International Airport, where the only thing standing between you and the last plane out of the city is a murderous army of the undead.

Writings on the wall
Several instances on the roof tops of dead often say "help need food" or S.O.S. There are also many writings about how a bomb will be dropped on the airport. It's that their predicitions were true as the survivors witness the runways nearly obliterated, however, this could be due to the fact that planes were crashing during landing (As witnessed in the finale). The evacuation vehicle for this mission is a parked military transport aircraft, suggesting that the bombing (if planned for) hadn't occured yet.

You will also notice one of the later safe rooms with the writing "WE ARE THE REAL MONSTERS" and various messages below it telling him that he is a moron, telling him that the Infected are the monsters, and one tells him that he wishes that he is dead now. Beneath all that is a sentence that states "I miss the internet."