I know the rationale behind running JFK as summer only as it's primarily a leisure route, what I can't quite get my head round is why the service isn't offered around Xmas and New Year, the demand at this time is massive from m experience....
American and also Air Canada shift a lot of their metal from East <-> West to North <-> South as the Carribbean holds an obvious attraction for frozen North Americans in the Northern Winter. This allows the aircraft to be used fully across the winter season and not just for the mental period over the holidays.