The problem I have found with inflatables is that they don't breath and that in turn causes sweating/moisture issues especially in warmer weather.
Repurposing clothing has always been a go to method particularly when backpacking.
I've avoided using down because as previously mentioned, the "downside" of moisture/cleaning while on a trip. And since it has usually been another piece of down gear that was used as the pillow, it was a double "hit" when there was an issue with moisture. And being a "hot" sleeper means this is a frequent problem.
Nowadays, the trips are shorter, often car camping and the weight of a smaller compressible is a tolerable allowance. One thing for certain though, a smaller pillow works better for me in a gathered end hammock. The larger pillows were just too much.