The horsepower required by your engine cannot be determined so simply; we cannot answer the question.
In order for your ship to fly, it needs to produce as much lift as its entire weight. In order to produce lift, it will need to use some kind of an airfoil, which will presumably require that the ship be moving through the air (like an airplane), or for the airfoil to be moving through the air (like a helicopter). In either case, you need to figure out how much power is required to push the airfoil through the air at the speed needed to generate the required lift. This depends upon the airfoil design, the drag coefficient of the ship, the efficiency of your means of propulsion, and all kinds of other factors which we cannot deduce from your post.
- Warren