Which of the following is NOT a common type of fabric used in aircraft covering?

Silk is not commonly used in aircraft covering due to several practical considerations. While it has been historically significant and is known for its lightweight and high strength-to-weight ratio, silk lacks the durability and resistance to environmental factors that modern fabrics provide. Current aircraft covering practices favor synthetic materials like polyester and nylon, which offer enhanced durability, UV resistance, and weather protection. Cotton, although it has been used in the past, is less common in contemporary applications due to its susceptibility to rot, mildew, and increased weight compared to synthetic options. This shift towards synthetic fabrics has been driven by advances in materials science, leading to more reliable and long-lasting aircraft coverings.