In aerodynamics, form drag, profile drag, or pressure drag, is a component of parasitic drag created by wind hitting the body. The general size and shape of the body is the most important factor in form drag; bodies with a larger apparent cross-section will have a higher drag than thinner bodies. "Clean" designs, or designs that are streamlined and change cross-sectional area gradually are also critical for achieving minimum form drag. Form drag follows the drag equation, meaning that it rises with the square of speed, and thus becomes more important for high speed aircraft.