I used to be like you, had a panic attack on a plane back from Greece once. The best thing you can do is a longhaul flight! It was for me.
I'm going to Barcelona tomorrow and the anxiety is setting in a bit, but I know ill be fine.
The way I calm myself down is by thinking of the following:-
- you're not gonna get there any other way, not quickly anyway.
- if you're uneasy of turbulence etc, look to see what the cabin crew are doing. If they're still up doing their job then everything's fine. You only have to start worrying if they look worried. I've never EVER seen one look worried!
Enjoy the flight, I'm sure they'll have on board entertainment to keep you occupied. When I flew to Chicago I watched about 10 films one after the other, before I knew it I was there!