Hi Gilby! There are two airboat tours that I have found to be exceptional. The first is Boggy Creek Airboat Tours (http://www.bcairboats.com), who are a family owned business with true pride in their offerings. I have toured with them a number of times and always found them to be an excellent outfit. I just did another nighttime tour this past July with my parents and my DS, who talked about it for weeks afterwards. If you go when they offer their nighttime Jubilee you're in for an even more memorable evening.
Another great option is Black Hammock Fish Camp (http://www.the blackhammock.com) with Cptn. Joel Martin. You have the option of east or west Lake Jesup, where the largest gators I've seen (and the most bugs!) can be found. Cptn. Martin gives a fabulous one hour tour and may even have a baby gator on hand for some wonderful pictures (hang on to that tail!!).
You are so wise in looking into an airboat tour. It's a real slice of natural Florida, completely uncontrived, and the perfect compliment to time spent in the parks.