This MAXOAK 36,000mAH High Capacity battery is a beast. This one specifically comes with two different MagSafe power cables to give you extra run time on your MacBook Air or even my (late 2014) MacBook Pro Retina.
The MAXOAK 133Wh Power Bank 16.8V (3.5A) and 14.8V (3.5A) output along with two USB ports (2.1A) for charging other devices like your tablets, phones, etc. I could always use some extra battery life when traveling, editing, or when capturing footage on location so this will work out well. (Keep in mind though, that most airlines may limit the size of batteries you are able to fly with at 98Wh. This is rated at 133Wh.)
There's a ton of high capacity batteries out there, but at least this one comes with the MagSafe cables. Which is strange because I thought the MagSafe cables are Patented and didn't think anyone was able to make them. Maybe that's not a problem anymore, or maybe they just didn't catch this one yet. Check out the many reviews on Amazon http://amzn.to/1nLOzwo