Try to always think about pleasant. The most person is scared by the unknown. Therefore, you need to better know what you are afraid. You need to imagine what will happen at the moment when you find yourself in the plane will happen a few days before the intended departure date. Here you go on the plane, sit in your place, fasten your belts. If at that moment you are scared, then immediately begin to think about something pleasant. For example, imagine how you are lying on the beach, drink a cool cocktail. So, you calmed down and you can continue to submit the following stages. The plane takes off, flies, then lands. And every time, as soon as you start to become scary, immediately imagine something good and pleasant. Try to train at least several times a day, and then on the plane it will be much easier for you.