Strange noise from front - thoughts?

[MacGrad]

Driving my 2002 yesterday, and starting hearing a strange "whooshing" noise from the front of the car...

Best way to describe it is that it sounds like an air flow is being interrupted (like a flap opening and closing), and it speeds up/slows down according to the car's speed. There's also a slight metal vibration sound from the front, but that I just noticed, but not sure if it's coincidence or related.

(Update: wife mentioned that she tapped the front end on one of those low concrete parking things, so could something be knocked loose...)

Checked the side intakes and front of the grill, but it doesn't appear that anything is blocking them... Also sounds like it's coming from the right side of the vehicle. No CEL light on the console.

Any thoughts? Car is going in for oil change in next couple of weeks, unless this is something to get checked now.