I went by harbor freight the other day and picked up a couple moving blankets, the are $8.99 a blanket.
Came home and cut it to fit my yellow twin f-18 wing, with one side larger to make a flap. Pulled out my wifes sewing machine and made a pass all the way around the edge....pulled it inside out to hide the ugly seam, slapped out velro and bam wing bags made in about 20 minutes... not bad for $8.99
one blanket made the two wing bags