Very nice find! I have used Z-brush and Mudbox for awhile now and this looks to have just as good functionality as those big box programs. as for using it for FSX, you might be able to get away with creating a Pilot, but the trick is to use a program such as this to create a very high poly model, then Texture bake it to a low poly model so that you get what looks high-poly, but it actually low-poly. That is the bare bones version of that method. Because of the level of detail that is needed, you end up splicing a mesh in the thousands and FSX does not like that too much, it can be done, but don't plan on playing MP with a bunch of High poly planes around!