Aircraft Manufacturer built their planes to safety specifications and one of them are the airplane seats cushions. They have to withstand high G-force impact which means they are hard and uncomfortable. So having a comfortable airplane seat cushion can be bliss and in comes the Skwoosh Pilot Seat Cushion
SKWOOSH are made out of fluidized gel and are more comfortable because they relieve pressure on the tailbone to help maintain circulation. It reduce numbness and lower back discomfort caused by prolonged sitting and prevents those stiff legs when you get out of the plane. It fits all aircraft seats, including those with a central harness attachment and it conveniently fits in most flight bags and carry-on. The non-skid bottom makes it stay put, ensuring no movement during use while the low profile allows for normal seat position.
I have heard of some complain of the stitching that parts after extended use but mine has not shown this after 2 years.
There are more expensive options than this but I do not see how it can approve your comfort level to justify the extra cost.