The higher wing loading on larger planes is partially due to the displaced wing area, ie a wing with a NACA 0011 airfoil, 48" WS, 12" root & 8" tip will displace 366 cubic inches of air while flying. For arguements sake, lets say this plane weighs 5 lbs, so the wing loading would be 24 oz. a sq. ft.

If you increase the wing by 2x, (to a 96"ws, with a 24" root & 16" tip) the area doesn't double (remeber wings are 3 dimensional) but increases by 2^3, or to 2,930 cubic inches. Let's say this plane weighs 27 lbs. The wing loading would go up to ~32.5 oz. a sqft., however, if we were to look at the weight per cu. inch of air displaced by the wing, we would see that the larger wing is actually carrying substaintailly less. The 48" WS would have to carry .2186 oz. per displaced cubic inch of wing area, while the 96" WS would only have to carry .1474 oz. per cubic inch. The small wing is actually carrying almost 50% more weight per cubic inch of displaced air! It's an over simplification, and I'm not qualified to totally explain it, but hopefully you get the point. Bottom line is, everything else being equal, bigger flies better.

Rick