Gently roll your head a few times. Close your eyes and focus on your gentle breathing as you invite your body to feel relaxed, warm and heavy for the next half a minute. Take supportive actions. Reduce caffeine and alcohol intake on the day of flight. Greet the flight crew and captain when you board, and look in the cockpit.
Some people find it helpful to confess their fear of flying to the crew.
In addition, you should decide in advance where you will sit. An aisle seat allows you to move about the cabin more freely. The window seat allows you to control the window shade. It's also best if you avoid detailed press coverage about airline accidents. You don't need to shun it but the mind has a way of remembering the strongest emotion.