True Story
When Frontier started, or more accurately, before it started, I was on a layover in DEN with a former Eastern Airlines captain. He was good friends with the new Chief Pilot of Frontier ( also former Eastern ). In the bar the chief pilot very specifically said that he had a list he was going to hire from. When they started all of the former Eastern pilots at my company went to Frontier. Later some of the guys at that same company also went to Frontier using their friendships with these former Eastern guys.
I'm sure it is a little different now, but that does illustrate how hiring is done at airlines, especially small ones and start-ups.
Typhoonpilot