If working on breathing exercises is not the best choice for you try this meditation technique.
Meditation
Choose a quiet spot where you will not be disturbed
by other people or by the telephone.
Sit quietly in a comfortable position.
Eliminate distractions and interruptions during the
period you'll be meditating.
Commit yourself to a specific length of time and try
to stick to it.
Pick a focus word or short phrase that's firmly
rooted in your personal belief system. A non-religious person might choose a
neutral word like one, peace, or love. Others might use the opening words of a
favorite prayer from their religion such as 'Hail Mary full of Grace', "I
surrender all to you", "Hallelujah", "Om", etc.
Close your eyes. This makes it easy to concentrate.
Relax your muscles sequentially from head to feet.
This helps to break the connection between stressful thoughts and a tense body.
Starting with your forehead, become aware of tension as you breathe in. Let go
of any obvious tension as you breathe out. Go through the rest of your body in
this way, proceeding down through your eyes, jaws, neck, shoulders, arms,
hands, chest, upper back, middle back and midriff, lower back, belly, pelvis,
buttocks, thighs, calves, and feet.
Breathe slowly and naturally, repeating your focus
word or phrase silently as you exhale.
Assume a passive attitude. Don't worry about how
well you're doing. When other thoughts come to mind, simply say, "Oh,
well," and gently return to the repetition.
Continue for 10 to 20 minutes. You may open your
eyes to check the time, but do not use an alarm. After you finish: Sit quietly
for a minute or so, at first with your eyes closed and later with your eyes
open. Do not stand for one or two minutes.
Plan for a session once or twice a day in preparation for your flight and add the breathing exercise practice when you feel confident.
Here is a video for you: http://www.youtube.com/watch?v=Zh-klfBJlHc