My legs feel more sensitive to air flow when wearing fishnets than when bare. The pattern they make on my leg is similar to that of the dimples on a golf ball, which induce a turbulent boundary layer on the surface of the ball to reduce drag.
If fishnets are causing the same effect, there would be changes in heat transfer but I'm not sure I'm up to digging into the differential equations.
In short, I'm thinking about wearing fishnets while cycling for aero.
I'm not especially hairy but this is a good point worth considering. Very little on my thighs where I still feel a cooling effect.