The first Macbook Air was introduced at the Macworld Conference and Expo in January 2008. It was touted as the "World's Thinnest Notebook" by Apple. When you register your Macbook Air with Apple, you will receive important updates, technical support and free tutorials. To register your laptop, you must find the Marketing Part Number (MPN).
Click the "Finder" icon on the Dock.
Select "Applications" on the left side of the Finder window.
Scroll through the Applications and find the "Utilities" folder. Click on "Utilities."
Click "Apple System Profiler" and select the "System Profile" tab.
Locate you Macbook Air's MPN in the "Hardware Overview" section. The MPN is next to the Sales Order Number.
If you still have the original Macbook Air box, you can find the MPN on the label on the outside of the box. The number is located next to the barcode, and begins with a letter.