Even after it all hit the fan, there was still a space program going. The people with money needed someone to ferry them to a whole new planet to ruin. There was a mad rush for the pilot jobs. Not only was there the possibility of breathing air without a filter mask at some point down the road, but you might get to save up enough to get off Earth for good.
There were obviously more applicants than open spots, but you got to keep the hat from the basic training camp.