As I have been collecting data on planes into Excel, I am noticing that larger planes have higher wingloading. Of course there are exceptions, but there is a definite trend.

For example:

U-Can-Do 46 at 5.5lb and 904 in^2 is a wing loading of 14oz/ft^2
H9 FuntanaS 90 at 9 lbs and 1107 in^2 is a wing loading of 19oz/ft^2
CH Vision 3D at 14 lbs and 1300 in^2 is a wing loading of 25 oz/ft^2
H9 33% Edge 540 is 23 lbs and 1730 in^2 is a wing loading of 31 oz/lf^2

Is this simply because as scale (size) increases, the volume (sort of mass) goes up by the cube of the increase and the area only goes up by the square?

ie. take a sheet of material, 10"x10"x1". Volume = 100in^3 , area(flat ways) = 100 in^2 so Volume to Area is 1
double it's size (all 3 dimentions) to 20"x20"x2, Volume = 800in^3, area is 400in^2 so Volume to Area is 2 (hence higher wing loading?)