Wow, it sounds like you're already a pro at all the usual coping techniques. Sorry they haven't been helpful enough in very high stress situations. Traveling gets too me too; just too many people too close to me. I sometimes get irritated/angry--it's my defense against the fear. Not a helpful habit, though!

I have a beaded bracelet that I can run my fingers along as I do affirmations. I do it during peaceful times; then when I do it while stressed it brings up the feeling of peace. It gives my something physical to pay attention to and occupies my mind. I find it easier to remember my sayings with the beads, too.

I also count when I'm panicking. Gives me something to focus. I can't listen to music when I'm really freaking out, but radio shows with people speaking helps a lot.

I think you know that what will help most in the long term is "desensitizing" yourself. Are you working on your root problem of dealing with crowds and stressful places? You can't do exposure for the cramped plane ride, but you could ride a bus (eventually if you're not up to it now).

Good luck working on this!