Air Force Cap ~ U.S. Air Force Veteran Cap ~100% Cotton Twill Adjustable Military Collectible Hat ~ With Solid Back Sytle! by Rush Industries. $20.96. Show your pride by wearing this honorary cap! Each cap is meticulously crafted, solid 100% brush cotton twill. They have a sporty look with a military visor made of all-weather polyester fabric from front to back. Fits all sizes with its easy adjustable strap. (Not sold in stores).