The article touches on this. Pilot wages are very similar across major US airlines due to heavy unionization and pattern bargaining, so labor is more-or-less a fixed cost (and not the biggest fixed cost). Additionally, pilots can and do take pay cuts in lean times. The pilots at my own airline saw a 20% pay cut in the contract following 9/11 and very reduced wage growth for a decade after that. Management took something like a 5% cut and kept the retirement benefits we lost.

Edit: I thought I recognized your name, I see we discussed pilot unions together on HN a few years back. Can I ask what you have against us? Out of genuine curiosity.