There is a Visitors Center in Everglades City.
http://www.nps.gov/ever/planyourvisit/gcdirections.htm
They have enacted severe regulations on the air boat operators. The air boat rides are not what they used to be. Of course, if you haven't ever been on an air boat then you won't know the difference. There are air boat operators on the Naples side. There will be plenty of tourist brochures for them in Naples.