NO, I think AA will still have a hub in San Juan. People tend to misuse the word "hub". A hub is simply where small feeder flights meet longer range flights. Usually, though, this coincides with the airport with lots of flights. Technically, Boston, while not being a hub city to any airline in the Chicago, or Washington sense of the word "hub", is a hub to American. With American Eagle's acquisition of Business Express Airlines, a person from Bar Harbor, Maine, can now fly to Boston on American Eagle, and connect to flights to Los Angeles, or London. In Boston, we now have regional flights, meeting loger range domestic, and international service, by which is the defintion of an airline "hub", even if it has less than 200 flights a day.
Anyways, I believe that the Caribbean is an important market for American, and as long as they operate short hops to local islands, connecting to American's long range flights to the mainland, American will always have a hub in San Juan. Plus, Miami is too far away to profitably serve many of the markets American Eagle serves from SJU.
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