Your sexuality is of little or no consequence to a career in the RAF, or the wider world, unless you yourself make it so...
My missus is an ex-teacher and she taught me the importance of the phrase 'image is reality'. By what measures do you want your friends and colleagues to form their opinion of you ? Will your sexuality come top in how you define yourself (gay, then officer, then pilot etc.) ? If so, then others will pick up the same prominent features, but from their own perspective, whether that is tolerant or not.
This does not mean hiding what you are, btw. The most heinous crime I could commit as a reservist would be to say 'I can't do that, I'm only TA' because I would be defining myself by my difference to my Regular compadres, rather than emphasising the strengths and skills that I have.
Make sense ?
FP