I would recommend a couple of books to read that deal with this issue: Ask the Pilot
And Don’t Panic (Deals with panic attacks and I believe there is a chapter on flying).
Fear of flying is irrational and has lot to do with wanting to controlling your environment. When you fly you give up that control, to the pilot.
My wife has this fear and deals with this by not drinking any juice, caffeine, and alcohol 24 hours before and the day of travel. This will prevent your being on edge or induce a panic attack. The other thing she does is take 1 5mg Valium an hour before leaving for the airport and another one before take off.
Good luck!
R