Realistic or not, just like combat trim it should be in the GAME if it will be an attractive addition to people, and it is. (And yes, you purists can toggle that sound slider to zero and not worry about it, just like disabling CT.)
Still, I was reading the book Samarai! and he seemed to mention the roaring sounds of the other planes spiraling around him in a big dogfight.
Ut oh, so it may in fact be more realistic anyway.