One of the greatest 'non-military' fixtures of WWII was the creation of nose art on airplanes. Aircrews in World War II decorated their planes with pictures of pinups, typically modeled after the popular "cheesecake" art of the period, or popular actresses of the day, such as Betty Grable. Cartoon characters were another popular subject. Air Force officials tolerated the nose art in an effort to boost morale. Eventually, the AAF issued Regulation 35-22 in August 1944, allowing nose art, but discouraging particularly risque art. Nose art was the exception on the Navy and Marine aircraft because of the directives prohibiting it. Nonetheless, WWII is often considered the heyday of airplane nose art.