just saw a big industrial fan being installed underneath the hover craft. dont know if a big fan or a propeller

I've actually worked on them before...lol ;)

That was a surprise answer :-)

Lol :)

its just a trick question. I SAID UNDERNEATH so its under the hovercraft, not on the outside

Ok, I didn't say on the outside, I do see what your saying. Lol. The one I've worked on had the lift fans in the deck of the craft and some smaller ones will have ducting that takes a portion of the air from the propeller and use it to lift/fill the skirt. :)

so whats better a turbofan or propeller

Well, it really depends on application, but, assuming that the propeller is a turboprop, you can't really go wrong with either. The turbines will are will operate way longer than any piston engine. In aircraft for instance, piston engines will need overhauled every 1,000 hours, turbine/turboprop/turbofan, overhauls are anywhere from 10,000 to 100,000 hours! But back to the turbofan/propeller, like I said it's all about application, which one is more efficient for that particular job. :)