Sorry if this link has been posted before. I don't have a cushion, but am going to order one today to give it a try as I have a lot of pain in my coccyx area, and generally around there. Also, am going to fly with two hours of sitting, in ten days, and hope it will help on the plane.
http://www.icnsales.com/chair-cushions/
Em

Now I see they are out of stock of most of them! Will have to search again. Drat!!

Managed to get my cushion, but it is a little to hard for me, so back to a softer one for now while I consider ordering another. What money gets spent on solutions!!