My MBA's hinges BOTH broke. I'll tell you one thing, this is absolutely a manufacturing/design flaw. Right after I bought it, I started working as a freelancer and did not need to carry it anywhere, so it just sat there. All I ever did, and I mean EVER did, was open and close it... which is what I assume is "normal operation of a notebook".
First the right hinge broke- completely out of the socket. The today, just as I was bringing into my local service repair center, the second hinge bulged and the metal clasps are popping out of the plastic.
I can't tell you how furious I am that Apple denies there is a problem with the Rev A MacBook Air. They vehemently deny a problem exists, insist that I "forced it open too far", and blame me for the issue. The service provider (Charlotte Street Computers, Asheville NC) is great and I highly recommend them, but Apple is trying to pull a fast one and I won't have any of it.
I'm going to continue to fight as long and hard as I can.. partly because I do not have $800 to pay for an entirely new hinge/screen. This is asinine, and the first time that I can really remember- or have heard of- Apple doing their customers so wrong. Even if they fix the Air for me without a charge, I will still be upset at they way I was treated. We all pay a high price for Macs, even if they are worth it, they problem should not exist on a $1,800 laptop. It's like a ticking timebomb is built into the notebook.
I wrote a small blog post if you're interested:
http://blog.jeremybuff.com/macbook-air-hinge-problems/