While driving the other day I noticed a loud vibration/flapping sound behind my left ear. Started at about 30 mph and went away if I put my arm on window ledge. Obviously the wind was getting to something. To make a long story short it was the strap that holds the boot on. The solution was to undo it and put one twist in the strap and re-attach.

This was kind of hard to find because when I stopped to check it out nothing seemed loose. Don't know if anybody else has seen this but it bugged me for a couple of days before I figured it out.

 

I cannot remember who on this board suggested it, but I took the snap apart and put it on backwards so that you cannot snap the strap to the car without a 1/2 twist.

 

That's what I did, and I haven't had that problem since. The snap unscrews from the strap, and can be put on from the other side.

 

Yes, it definitely solves the problem.

 

I did that as well (take off the snap, put it on in reverse so the straps have a half twist when attached) and no more buzz.