If you look at apple's battery life page it states the MBA battery is removable, I thought it wasn't supposed to be?
Battery Lifespan
For Apple notebooks with removable batteries such as the MacBook, MacBook Air, and 15-inch MacBook Pro a properly maintained battery is designed to retain up to 80% of its original capacity at 300 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs.
The built-in battery in the new 17-inch MacBook Pro is designed to retain up to 80% of its original capacity at up to 1000 full charge and discharge cycles. The battery in the 17-inch MacBook Pro should be replaced only by an Apple Authorized Service Provider.
Battery Lifespan
For Apple notebooks with removable batteries such as the MacBook, MacBook Air, and 15-inch MacBook Pro a properly maintained battery is designed to retain up to 80% of its original capacity at 300 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs.
The built-in battery in the new 17-inch MacBook Pro is designed to retain up to 80% of its original capacity at up to 1000 full charge and discharge cycles. The battery in the 17-inch MacBook Pro should be replaced only by an Apple Authorized Service Provider.