We had an old 10 HP Briggs horizontal shaft electric start engine from an old riding mower that looked like it would fit the bill. We bought the plans for their UH10F craft. We liked it because it only uses one motor. Most hovercraft use a separate motor for lift and thrust. This one directs approximately 1/3 of the thrust air to provide both lift and inflating the skirt. Most of the materials could be found at the local builders supply.
The only parts we needed to buy from Universal Hovercraft were the Plans, propeller, propeller hub, and the skirt material. Although it busted our $500 budget we decided to purchase their materials kit which included all the epoxy,fiberglass , screws, and glue. The skirt is the heart of this thing and we didn't want to save penny's on something this critical. It was a fun project for the both of us. It would be a great Father and Son project.