Mark G
Do not write the letter until you have done something to alleviate the problems you are having. If you can get on a desensitising course, great! (Do not confuse with a fear of flying course - I'm sure you wouldn't.) Or, do some light aircraft flying - 10 hours? - and see how it goes. If all is well, write the letter and say that the problem has been cured and explain how. Without either of the above the reply from the RDAF(?) will be a 'Sorry, no thanks'.