There are small airlines serving Florida (they come and go) but sadly TLH and even GNV air service is pretty much entirely connections through ATL and CLT. Flying between Florida citites can be a real challenge.
Major cities, no. But smaller, yes. But given the abundance of interstates between major cities and the Florida Turnpike, many of us just drive.
Kinda silly to fly from Miami to West Palm when it's about 80 minutes on I-95. Or 3 hours from Orlando to Miami.