Interesting. I know for a fact Virgin America pay went up several times without a union. I also experienced my pay being raised, significantly, while I was working on a contract overseas.

It seems to me that pay is overwhelmingly determined by the financial health of the airline combined with the supply and demand for pilots. For example: after 9/11, many airlines were struggling financially and many pilots lost their jobs. Despite union contracts and the ability to collectively bargain, pilot pay dropped significantly. Now airlines doing very well financially and the supply of pilots, at least on the lower end, is limited. The result is pilot pay is increasing. The next time airlines begin to struggle financially, pay will decrease again. History shows that it will, and only a fool would seriously believe otherwise.