This self-inflating lumbar back pillow got me through over 24 hours of international travel in coach.
I spent a lot of time in coach over the last week or so. My back can't really take a lot of these shenanigans, but I came prepared. I knew exactly where in my kit the McKenzie AirBack was stowed, so I could grab it as I hit my seat. Helping preserve my lumbar lordosis while I sit in terrible airplane seats is a must.
Depending on your own back you can put a little, or a lot of air into the pillow. I do not inflate it very much, a little goes a long way. Remember, as cabin pressure decreases, your pillow will inflate more! Becareful not to over inflate!
Similarly, I find it easier for stowage to deflate the pillow at the beginning of descent, the lower pressure makes it easier to get the pillow packed tiny at sea-level.
Using this while flying leaves me with less pain radiating into my legs. I purchased a self-inflating when my last OG Airback was lost.