Hi Dew,
I hope all goes well with your sisters surgery and that you have a safe journey.
I have flown to Vegas from the UK with RSD so can relate to feeling nervous. The plane journey was pretty tough on me and it REALLY limited what I could do whilst we were away. I think I was in a flare for a good few weeks afterwards also. My parents wanted to go to Florida later this year but I just don't think I will be able to cope with it all that well as it is a 10 hour journey, plus it will be really hard for me to get time off college. I really hope you don't end up in a flare like me!
If you can, try and move as much as possible during the flight., I know it will be hard but it should try and help with the swelling hopefully. Speak to your doctor also to see if he can suggest anything to help you during the flight. I know my doctor created an 'emergency RSD pack' of pain meds for if I went into a bad flare.
Your sister is really lucky to have you and i'm sure she appreciates everything you are doing for her, especially seeing as you have RSD and have a lot going off in your own life right now!
I know you are going away for your sisters surgery but try and have a good time yourself, in between all of the hospital visits - you deserve it!!!
Take care hun and please keep us posted as to how the journey goes and send our love onto your sis and family!