Many of these skins were designed for Windows 95/98 environments. If you are running the game on modern hardware via DOSBox or wrappers, ensure the file paths match the emulated drive structure.
Most likely the Jane's Combat Simulations title Advanced Tactical Fighters or its expansions ( Gold , NATO Fighters ). Wiler.ATFPack3_Skins.2.rar
While specific contents vary by pack, these archives generally include: Many of these skins were designed for Windows