In regard to paragliding, the area of the sail (on the wings that people use to paraglide) is used to determine what size wings the person should use, which largely depends on their weight. These wings are regulated according to how much weight it can carry (which includes the weight of the pilot, of the gear, and of the wing itself). There is a maximum and a minimum weight for each of the wings, which ensures the safety of the paraglider.
