AA has a nice little operation going on at FLL. In addition to four hubs routes...Dallas, O'Hare, San Juan, and St. Louis, there is mainline to LaGuardia (which gets a fourth daily in November), Boston, and Los Angeles, and Eagle to Raleigh and Nassau. Caracas service is on again off again. It was supposed to start 15Dec01, then 16June02, then 15Dec02, and now it has been put off again. In the past they also had Freeport (cut last September) and Washington National (cut a few years back). I personally think a daily 757-200 to San Francisco would work very nicely. American Airlines is able to get a lot of customers at FLL because they attract thier huge Miami FF base who would perfer not having the hassle of a hub when they can go to LAX through FLL. Sure, MIA offers more options (5x daily vs. FLL at 2x daily), but it works very well, IMO. I do think AA could do more with thier FLL operations, but it comes down to yield, and MIA offers high yields, something that no other large Florida airport does.
As for the business community, a large part of it is in Ft. Lauderdale. The banking and entertainment industries, South Florida's two biggest (after tourism), are all in Miami (and those two industries probably bring in better yields than others), and so are Lennar, Burger King, and Ryder Systems, but Ft. Lauderdale has the bulk of South Florida's big boys. AutoNation (Miami's largest company), TriArc (Arby's and a few other fastfood chains), Sports Authority, Office Depot, ANC Rental (National Car Rental and Alamo Rent-A-Car), and Citrix Systems, among others, are all in the Ft. Lauderdale area, not Miami. There is also FPL, which is closest to Palm Beach.
Segmentking, that is only during the summer. During the winter, AA has dailies to Boston and Dallas, triple daily to LaGuardia (the third frequency is new this winter), and double daily to O'Hare. LaGuardia starts 01Nov02, the rest 15Dec02. There was also a short lived American Eagle MIA-PBI service a few years back that competed with Tri-Rail.