Seldom
Not for the wider RAF no, but for actual combat fighters, yes.
You may find this hard to understand, but the folks who hit me during my military career, only ever did it after I had made repeated or really stupid errors. If I needed to be taught something they would teach me, and spend as long as it took to make me understand what I needed to know. If I did something really silly, then a kick or punch could come my way. It is very worth noting that I could be stood/laid next to the person who had hit me while under fire, and they not only wanted themselves to come out the other side unscathed, but wanted this for me too. Some of these people depended on me to be spot on in a crisis, and me on them in return. I don't ever remember being hit by someone in anger, or of feeling bullied by anyone.
I'm not sure how some RAF SGT hitting an airman for signing out the wrong sized bolt or screw would help, but a swift punch for failing to point out a trip wire or mine is a bit more relevant (even on exercise).
One example that stands out was during chemical warfare training. Whenever I used to open a new plastic packet of gloves, noddy suit or facelet mask etc I always used to rip open the packets with my teeth (only realising I was doing it as I bit the packet open). Clearly this is not big or clever in a chemical rich environment, but I just kept doing it.
One such time I did this, I was rewarded with a swift tap to the nose with a fist, and perhaps oddly to you I never bit open packets again. Maybe its important to differentiate between the above non personal, open to everyone and guidance based system, as opposed to one person singling out one other individual for repeated harassment.