Fear is often irrational, and anxiety has a way of undercutting common sense. Still, the fear of the unknown is the greatest fear, and anxiety thrives on "what ifs."
Learn as much as you can—about flight mechanics, about how airlines and airports work—whatever it is that scares you most, learn the most about that. By turning the unknown into the known, and you can better fight it.
A big part of aviophobia is called "anticipatory anxiety." Leading up to the flight, it's easy to imagine all sorts of crazy stuff. Education will help here, as will relaxation techniques, flight simulators, and even group therapy.
Try listening to music or reading a book to take to keep your mind from wandering while waiting in the airport.
There are multiple therapy-couch phrases that are tossed around as jokes: "deep breaths," or "go to your happy place," for example. But these things are brought up repeatedly because they actually work.
Regardless of how you clear your mind, your attention is going to be focused on something that isn't triggering your fear. If your senses are focused on your breathing, you'll have less bandwidth to worry about that turbulence you're feeling.
We have a whole guide to surviving long-term flights. Most of it involves becoming as comfortable as you possibly can, from springing for nicer seats to bringing things along that put you at ease.
If you can make this tiny space yours, you'll be operating from a more comfortable baseline than you were before.
The bulk of anxiety lies in anticipation. If you let yourself cancel flights out of fear, then you experience the anxiety without having the "that wasn't so bad" experience that counters anxiety.
Each time you cancel, the dread reinforces itself, growing stronger. The only way to combat this is to follow through.
