Kim, try not to worry too much (easier said than done I know) - anxiety and stress will exacerbate your CRPS symptoms on top of anything else.

A friend of mine has CRPS (one extremity) and went on a pretty normal flight - she didn't suffer any major problems. A little more pain than usual, and she took it easy for a couple of days afterwards, but otherwise it was ok. If this flight is something you have to do, and you have taken extra painkillers in advance and have something in standby you should be ok.

I would say to take a lightweight shawl or something you can put in a bag - the air con on planes always made me feel chilly pre-CRPS days! Also headphones with some calming music to block out the relentless noise of the air system and other people, along with a good book Set an alarm on your phone so that you can fall asleep if possible but know you will awake in time for landing. Also take some chewing gum - even if you don't usually use it - its great for coping with the pressure changes in your ears as you ascend and descend. Keep moving your feet and ankles gently and rotating your wrists to keep blood flowing, and ask the stewardess for a pillow or blanket etc if you need soft support for your arm.

Fearing the journey will only make it worse. You are taking the right approach in being so prepared though, and hopefully that will pay off.

Take care of yourself and I hope it goes well

Bram.