I have read several threads in RCU that discusses polyesther dress liner in place of Koverall. Some say it fills easier and is certainly easier to come by than Koverall if you get it at a fabric store. Evidently Walmart sells some but it is more open weave and does not fill as well. The material you get at a fabric store also shrinks well. I have used Koverall with good results and next time I have an approprite plane to cover, I intend to try dress liner.