Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Luck of the draw with the Air's. My 2011 creaked a bit. Tightening the base screws might help. The 2012 I'm sending back doesn't creak at all, yet.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.