Agribon is what you need. Its woven and breathable. There are all different weights. The heavier stuff is for frost protection. The lightest weight allows like 85% light transmission. It does not trap air or heat. That's what u need. Its cheap also. U can't see through it. It keeps bugs out. It makes water bead off. But it breaths enough that u don't need to have open vents.
you can barely see through the plastic anyways, i wouldn't bee too worried about a chopper seeing through it from however high up they are... also if you go with the double layer of inflated poly for the roof, nobody is seeing through it..