Please go to this Wikipedia article on Lift Coefficients, and behold the first formula. The last part of the equation has a "S" which is supposed to stand for "relevant plan area". Now, there was no explanation of what this "relevant plan area" is or means. I was guessing that it means the surface area of the airfoil, but this cannot be so, because as "S" is in the denominator of the formula, thus as the surface area increases, there is a diminished lift coefficient, and hence a diminished lift power (so my reasoning goes). I would write down the formula here, but for some reason Latex isn't working. So: what is the "relevant plan area" referred to?