While specific contents vary by pack, these archives generally include:
Extract the .rar file using a utility like WinRAR or 7-Zip . Wiler.ATFPack3_Skins.2.rar
Custom textures (skins) for various aircraft models within the game's engine. While specific contents vary by pack, these archives
Most likely the Jane's Combat Simulations title Advanced Tactical Fighters or its expansions ( Gold , NATO Fighters ). While specific contents vary by pack