My first concern (in freezing weather) would be the spray that blows out from under the skirts when you fly over open water..OR.. ponding water on top of the ice. The spray would instantly freeze on everything ...including those persons on board. Ever notice hovercrafts always have "windshield wipers"...and No defrosters.
As mentioned in the above post..I would be concerned with the skirts freezing to the ice when parked. I believe they would, but Not because of friction warming up the skirts and then freezing. The skirts are usually a dark color..black..and would absorb heat from the sun and gradually sink into the ice and
Stick Solid after a short time. I might even suspect that residual engine heat trapped under the skirt when the machine settles onto the ice would also cause ice melt and then freezing to the ice.
I like the idea of an airboat.....not necessarily the commercially available enclosed dedicated kind, (expensive) but a simple aluminum pram bowed "John Boat" with an
air cooled engine clamped on the transom, driving an AIR propeller. Like an Everglades Swamp Airboat but on a much smaller scale. No air rudders required at all...just steer it like a tiller steered outboard.. I have seen such
Air Drive Outboards available in the past.
NB
EDIT: Google "Outboard Air Drive". This is just one.
http://www.youtube.com/watch?v=ylvn0OuH2iE