I have an odd problem with a surface I created.

When viewed from the "outside" it looks just fine. However, when viewed from inside the object (aircraft fuselage), say like when your working in section view, the surface becomes invisible. You can see thru the entire part as if it was not there. Has anyone seen (no pun) this before? Know how to fix it? By the way, this is after the surface has been thickened.

Thanks