I have always been a bit leery on take-off (even before 9/11) and it helps me to close my eyes & listen to some music, immediately start reading a book or even semi-meditate. Sometimes it helps to sort of visualize it - imagine getting past it, being in the air. To relax. Other times it just takes time (for me) to get past the take off - to get through it no matter. To remember where ever I am going is worth it.
I'm not sure if any of these will work for the type of panic you describe. I hope some of the ideas the others have come up with will help you.
Fear can be very powerful. It can hold you back from a great many things in life but only if you let it.
P.