A few more points to consider:
1. Assume that you have two mold halves that meet the stated requirements, lay up a fiberglass/epoxy "skin" in each half, add any internal structure such a bulkheads (formers), join the molds with an acceptable method then, then when fully cured, you pop the fiberglass object out of the molds. Due to shrinkage during curing the object will be smaller than the stated requirements.
2. The wax layers, and the mold release material layer will also change the dimensions of the final object.
3. Even with structure added inside the object, there will be some small amount "oil canning" between the bulkheads.
There are many other factors to account for in order to arrive at an object that meets +/-0.0005" tolerance in all points on the surface of the object.
This is why I bring up the point that the specs seemed unrealistic to me. I don't intend to imply that it is impossible, just that it will be impossibly hard to accomplish with a cnc router table and the materials that are available on the open market. It really doesn't matter what the intended object is, glider or otherwise.
The company that makes the molds for us doesn't outsource jobs and I don't know the costs of making them. I would think that large size and higher complexity makes the costs go up exponentially.
CarveOne
CarveOne
http://www.carveonecncwoodcraft.com