Hiya!
Not overpowered at all. Useful in exactly
one situation: outdoors with normal weather.
Also, I feel I must point out yet again, that having the natural ability to
Fly (like an Aarakocra), does
not give the character the ability to
Hover. So the Aarakocra can forget about just "hovering 30' above ground and shooting arrows into the bad guys"; as soon as he stops to shoot, he falls. Now, how you deal with all that as a DM is up to you. Me? If he stopped, he'd fall. He could shoot while falling...with Disadvantage at a minimum...assuming he doesn't hit the ground first (he'd fall 350' in just under a round...4 to 5 seconds or so). In other words, he'd stop at, say 500', shoot at Disadvantage, with an additional -5 (long range plus falling...more than just 'disadvantage', I'd rule). Then he'd have to make an Intelligence save at DC 20 or go splat after obviously miscalculating his falling distance/speed.
But that's me.
Oh, I'd also not let an Aarakocra Monk add the monk movement to flight. If the player fussed and whined about it though, I'd let him get half the bonus, but NO bonus when he's on the ground (walking).
Yeah, I'm kind of a hard-azz DM. Easier to pull back a lot and give more later than give it all up front and try and claw it back out of the players cold dead hands...so to speak.
^_^
Paul L. Ming