[BomberBoy]

It's actually fairly easy to make your own default skins. In a nutshell, all you need are sets of 4 .tga files (one renamed .tgb, but it's still a tga) with alpha channels. The 4 files are different sizes for different LODs. The alpha channels are for transparency. These files would go into a folder structure something like this:

\MODS\-name of mod-\3do\Plane\-name of plane, including nationality-\-season-

example:
\MODS\B17F\3do\Plane\B-17F(USA)\summer

Let me know if you want a full explanation of how to do all this.