I've had several recent back and neck surgeries and can review almost every travel pad out there! For the BIS area, the therma rest inflatable pad is excellent. Easy to carry, can be used in the car on arrival, really takes the pressure off those bony parts. For the lumbar area, the inflatable has been my constant companion. Rolls up as small as my compression stockings, self-inflates easily to the perfect pressure.

That being said, in the acute postoperative stage I did rely on the purple pad (both seat and lumbar) for longer (>2 hr) flights. I tried various knockoffs first, both due to price and weight, but the purple pad does ease those hot spots when nothing else does. They are HEAVY though, and I used an under-seat roller bag to haul them around. (the doc said no lifting, but he didn't say no travel, and time off is time off!)

Now for my last confession. I also took an old memory foam mattress topper, about 2" thick egg-crate type, and cut it to fit my spine and hip area. It fit perfectly into a body pillow sized pillow case. I then used a compression sack from REI to squeeze it down, and carry it on to use in my lie-flat seat on transoceanic flights. Comes in handy when the airBnb bed is sub-par or you are on one of those rock hard beds in Italy. Hey, sleep is everything, my spine is shot, and I'm not going to stop travelling...