Allow me to clarify. Those magical, mystical "special cheerleading panties" are actually called spankies. Also known as briefs or bloomers.
Spankies are worn over underwear and are designed somewhat like a swimsuit, with stronger elastic around the legs to hug the buttocks and thighs and prevent uncomfortable movement. Moreover, they are designed (no doubt by magical, mystical elves) to prevent interested audience members from sneaking a peek of the girls' more private areas.
Most cheerleading uniforms require that the spanky be the same color as the skirt, so that the flashes of "panties" that occur during certain stunts do not cause distractions. From a distance, it's difficult to tell whether you're seeing just skirt, or skirt and bloomer. Some teams will attach a small patch, such as a pawprint or school initials, to the right or left thigh of the pants for decoration.
Male cheerleaders are, of course, not required to wear spankies.