Does noise mean less aero?

Sort of. More noise = more drag (sound waves carry energy, and that energy has to come from somewhere). But just because something’s quiet doesn’t necessarily mean that it’s aero.

I’d expect the drag from vortex shedding behind a rigid object to be fairly quiet but it can be non trivial (~1-2% of total drag from having someone sitting on your wheel and smoothing out your wake). Not sure how you’d really measure the acoustics of that aside from perhaps measuring the sound on a team pursuit by position.