It's an easy fix but takes two pairs of hands. Have a buddy twist the aile just past flat the opposite way of the twist. This will make wrinkles in the covering. Take your heat gun and heat the wrinkles out. It is important that your buddy hold the twist during the heating and until it cools. A pair of gloves will help since you may be heating next to his fingers. When he lets go it will spring back a little and it should be straight. You can do this several times if need be.

David