Years ago I spent a lot of time detailing interiors. I slowly progressed to a coat of something fuel proof and only then in areas of exposure. For example, the floor of the fuselage in limited areas but not the sides. I spend a lot of time altering structures to lighten things. Also failure planning and ease of repairs, particularly landing gear. It should pull out rather than damage the wing.

Incidentally, a few pin holes in the bottom of the fuselage, where fuel might accumulate is a good idea.

No more pilots nor cockpits. 'Maybe a clever picture of a cockpit taped to the underside of the canopy at most. Be creative.

ali