This is the pillow that I use on flights. It's been great.

Also always always always a window seat, noise cancelling headphones, eye mask, compression socks. I also wear layers to help with temp regulation.

https://www.amazon.com/Trtl-Pillow-Scientifically-Support-Washable/dp/B00LB7REFK

As for heating pads, I have this that runs on power banks. Also crazy useful.

https://www.amazon.com/Cordless-Sunbeam-Heating-Standard-Charger/dp/B08HR4RT4P?ref_=ast_sto_dp