MacBook Air 2011 doesn't charge
What's wrong with it? If it's a problem in charger, will Apple replace the charger. Mac is on guarantee.
MacBook Air (13-INCH, MID 2011), OS X Mountain Lion (10.8.2)
Yes. Apple will replace the power adapter if the malfunction is because of manufacturing defect.
Resetting SMC may help.
Reset SMC. http://support.apple.com/kb/HT3964
Choose the method for:
"Resetting SMC on portables with a battery you should not remove on your own".
Best.