those wing sleeves, sounds likes a pain to tailor. because I imagine its inner lining that's doubled up, the way wings are folded or its rigid structure, it's also confirmed that wings are part of the nervous system. got to be gentle and padded, hence the double lining. also it should be a little airy if they're literally cuts into the jacket, so like- double lining is like how a door is fitted so that one goes over the other, for a tight fit/proper insulation