I recently rode the AK ferry and shared it with an interesting boat. I thought it was an airboat, but after walking by it a few times I figured out it was a small hover craft.
Amphibious Marine - 14. Sure was cute. This one was decked out with all the bells and what not.
It off loaded in Juneau. The owner, a real nice guy, was pretty excited to play with it. Not the boat for everyone, but he felt it would be useful to him.
I got off the ferry in Whittier. The ferry Captain did a great job of docking with the snow/sleet blowing sideways. Took a couple of tries, but once he had it set up right it was smooth docking.
I helped a friend with wiring and getting his engines running on two hover craft then went on a few hunting trips with him. One started out as a 16 ft and ended up being a 20 ft x about 7 ft. The other is a 24 x about 11ft. They work really well, hauling quite a bit of weight and run fairly fast getting between 7 and 10 mpg depending on load and wind. They take very little water to run on and in fact will run over dry land. They will run through rock gardens in a river with rocks sticking up several inches above surface with no problem. Once you learn to drive one, they are very maneuverable. All in all very impressive craft. I believe they are about as good as it gets for river hunting in AK. When I get the time, I am probably going to build one my self. I am surprised there aren't more of them here.
This seems like a good place to ask, "Hovercraft or airboat?"
My choice would be a hover craft but only a twin engine one. You need to be able to separate the lift and the push to make them controllable. My friends 24 ft I have operated quite a bit. It will carry about 3000lbs of people and gear, run 55+ mph and get 7 to10 mpg. using a Subaru engine for push and a Kohler 25hp lift engine. It doesn't get stuck on sand bars as you drive them onto land to park them. I wouldn't get one less than 20' by 9' or maybe 10' unless I just wanted it for play as the smaller the foot print the less it will lift. They are not nearly as loud as an air boat as it doesn't take near the power to push them.
They also won't climb off a large/steep river bank or jump a 5' beaver dam. They don't like inclines either. Never seen one run over an alder patch and keep on trucking.
Size comparison, they don't carry the weight that an airboat is capable of.
The skirt can be a weak point.
Each craft has its limitations. Many companies have tried to put the hovercraft into service up here but none have been successful for some reason.
bkmail is correct, you need to keep them on flat surfaces. Trying to use one as an ATV won't work. Airboats will go pretty much where you point them if you have enough motor and deep enough pockets to pay for the fuel at gallons per mile and repairs on the hull from smashing rocks. Yeah, even with a plastic bottom cover. They both have advantages. Haven't seen a lot of commercial ventures with air boats either.