Its simple. There are only 5 cities in the USA that have non-stop service into Jacksonville through more than 1 airline. Chicago, Philadelphia, New York, D.C. and Atlanta. The theme is you can fly into Jacksonville from a hub airport, otherwise you are going to change planes in a hub.(ie Delta will take you through Atlanta or Cincinnati, US Air you go through Philadelphia, DC or Charlotte and so on.) check our website for a somewhat complete snapshot view of flight options in and out of Jacksonville International Airport
If you've ever landed on Miami or Orlando you'll know it's crowded at the airport. If you like it a little more relaxed you should try flying in to florida from here. You can get you suitcases from the belt whilst you travel compagnion can arrange your rental car...No buses to the rental station and wait twice..
I didn't fly into Jacksonville, but if you do, you might need to know the airport code, which is JAX.