is there a way to track stolen or lost MBA?

FIND_YOUR_IPAD, FIND_YOUR_IPHONE, FIND_YOUR_MAC are the same thing.

System Preferences > iCloud > check "Find My Mac"

Now you can track your Mac from an iDevice registered to the same iCloud account with the free Find My iPhone app.

You can also track it by visiting http://www.icloud.com on another computer's web browser.

For further information, please consult the support pages provided by Apple Inc.

http://www.apple.com/support/icloud/find-my-device/

concerning this functionality.

It would be in your best interest at some point to spend some time reading the documents in the support section of Apple's website.

Yeah Find my Mac needs to be enabled and so does Wifi. But I'll tell you right now, your only real chance of getting the Mac back is if you lost it and the person who finds it is generous enough to email you telling you that they found it (they can get your email either from your mail app or something). I've seen this happen with someone who lost their iPhone

This is worthless for the topic starter, but for the rest: please install something like Prey.