We used Progressive. Not sure if they are still around as that was a few years back. Cant find the price per acre but there is for sure a minimum price just to get them to come out whether its 1 acre or 1000. Each time they would push the spray button, it would record on GPS. So at the end, they gave us a nice map of their spray path.
No idea on an airboat. Someone here might can help if you give them a case of beer