Convert Sculpt model in a solid

[botesjohann]

Good day all.
Im currently busy with a model an I used sculpt loft to manipulate the shape to be able to get the  proper body shape I wanted.
But Doing this it caused to body to become a shell.
Can anyone help me by turning the shell into a body.
If attached the model /
As you can see at the Wing root and wing tip there is a Hole which Im unable to close
Thank you

[TrippyLighting]

I don't see you  creating  any geometry in the design you attached. 

Unless you share the complete model that allows to precisely reconstruct how this was designed I will not continue.

The ends can be patched with the so named tool in the Patch (surface) workspace.

[davebYYPCU]

This file is broken, has it been extracted from the real model? I presume @TrippyLighting already knows that.

The top surface does not meet the bottom surface, at the rear, so patching will need more work, but its already broken.