I bring ear plugs and wear them the whole time. Planes are very noisy and that noise adds to your stress. I put the headphones on over the ear plugs.
Keep your feet off the floor. Ya right! Here''s how/why. Try and put your feet on the metal brackets that hold the seats ahead of yours. If you''re in biz or first use the footrest. This helps you feel much less of any vibrations through the body of the aircraft. Those vibrations can increase your stress.
Bring your own reading material. Do not rely on what is left on the plane. It could be something that will increase your stress, particularly if it is aircraft accident related, like a stray news story. Some random things will stress you on a plane that will not stress you on the ground. Any negative kind of article can raise your anxiety level.
So bring your own that you have "precscreened" for content. I often do stupid books of crosswords. I never, ever do them unless I am flying. If my husband is with me, we do them together for extra distraction.
Yes, there is alcohol and yes, it will help. On one bad flight I had one glass of water and one of wine and I told the stewardess to just keep refilling if either went low. The deeply paranoid part of me does not want to drink cause if we crash I''ll need my wits about me, alcohol makes you bleed more, etc - only when I am very paranoid do I feel like that, but there you go, you can choose.
Wear sensible shoes. The kind you could run in if you had to. No nail polish. Wear comfortable natural fiber clothes. Keep your seat belt on the whole time.
Can you tell I hate to fly? Oh yeah.
Good luck - statistically you are in good hands.