More on topic would be this:
http://www.businessweek.com/articles/2014-02-04/airline-hub-loss-stalks-the-heartland-whos-next-after-united-quits-cleveland
Airline Hub Loss Stalks the Heartland: Who’s Next After Cleveland?
American is run by a core group of executives from US Airways, which dropped Pittsburgh as a base after its long-ago merger with America West Airlines. Highest atop the proverbial wall of worry is Phoenix, a US Airways hub that finds itself at a geographic and competitive disadvantage within the airline’s new network. Geographically, it’s between Dallas/Fort Worth—American’s home airport, and one where it dominates both financially and operationally—and Los Angeles, a huge market that could, under American, become a true hub for the first time.
“American seems to like what they see at LAX, where they’re now the largest airline,” says Seth Kaplan, managing partner of Airline Weekly, an industry journal. “And if they are going to compete at LAX,” that means Phoenix’s role could be diminished. Competitively, Phoenix is also a major focus city for Southwest Airlines (LUV) and a new destination for no-frills Spirit Airlines (SAVE), both of which limit the financial upside for a legacy carrier.