This has been happening more and more frequently lately. I'll plug my 2010 11" MBA in, and after a minute or two, the light on the charger will turn off. This doesn't happen every time, but I've noticed it happen 4 times this past week. Disconnecting and reconnecting the magsafe resolves the issue, at least until the next time. Yesterday, I ran the battery down until it was almost dead. I plugged it in for a couple hours, and when I came back, the battery symbol was "charging" but the charger's light was off. When I disconnected the charger, the battery was at the same place it was when I had left it a couple hours before. So basically the battery didn't charge, but the laptop was still being powered that whole time. Any suggestions? I'm out of warranty, and it doesn't happen that often, so I'm not sure I could reproduce the issue in front of a genius.