Many pilots who are a bit shorter, or fly airplanes with tall instrument panels or reclining seats (like a glider) may find themselves in need of a seat cushion. Pilots flying an aircraft with a stick instead of yoke should purchase a cushion with a cutout. Here are a few cusions I have tried and found to work well.
Proflight Booster Seat Cushion
This seat cushion is available in blue or red, and with or without a back cushion. It may be ordered in multiple heights, from 1 to 4 inches. This is a sturdy cushion. I own one myself. Cost varies depending on the options chosen.
Proflight Booster Seat Cushion with Cutout
This cusion comes in blue only and with an attached back cushion. It is quite tall with a 4 inch firm seat cushion. The cutout makes it ideal for planes with a stick instead of a yoke. I have flown with one in a Remos GX, Flight Design CTLS, and a Searey. It has a velcro strap to allow you to carry it folded up. Note that it is VERY thick, so unless you are very short in a plane with a tall panel, a shorter cushion might be better.