For such short flights, it wont be a problem with the ears. Just visit the ped before leaving to be sure he doesn't have an ear infection and otherwise, hís ears should be fine. It's a myth that they have to drink or suck on take-off and landing. Ear problems are highly overrated.

He'll be safer and everyone will be more comfortable if you can bring your carseat and see if you can use it on board in an empty seat. Wont you need it at your destination anyway? (Never risk car company seats, they can be expired, nasty, the wrong size, etc.). Double check that your carseat is FAA certified. Most are in the U.S.

On check in, ask how full the flight is and ask if you can be seated with an empty place besides you.

I go into way more detail in an article I wrote and placed on a blog for all parents to see. It's totally non-commercial and written to help out other parents (and my ex-coworkers, if parents have fewer concerns!)

http://flyingwithchildren.blogspot.com

Have a good trip and be careful with your little guy and that hot Florida sun!

DART Fares:
http://www.dartfirststate.com/information/getting_there/fares/index.shtml

Head down to Myrtle Beach or Fort Lauderdale. If you want to check out the west coast, go to San Diego. Plenty of nightlife in all of those cities, and more to do than just hang out at the beach.