I do much better if I am in an aisle seat - not sure if my mind perceives this as having more air, having an escape route of sorts, or what. I also try to follow certain established routines - for example, I always bring Games magazine and start doing a crossword once everyone is seated and the plane starts heading for the runway. This actively engages my mind in something other than what is going on (I bring books to read during the flight, too, but I have found that doing moderate to difficult puzzles is a better distraction for me when starting out). If I am fine once we take off, then I am fine for the rest of the flight.
I was on Paxil CR for a while and that did help with anxiety overall, but it is not something I wanted to be on forever... Unfortunately with your restrictions on meds, I don't know if there are any out there that can help you.
Hang in there. Good luck!