here is one way
The military decommissions lots of parachutes every year and they are available to purchase. The material is perfect for these covers. One parachute's worth of material will do a couple of aircraft. Its strong, very lightweight and can be cut and fashioned into just what you need. We used these when I was in the army and needed just this type of cover for our Hawks during the first gulf war. We went outside the system and had these made. cheers,