It was mentioned earlier, but I have the Tucano Second Skin sleeve. And there is a specific one for the Macbook Air. It fits quite snug, but is not difficult to put it or remove from the sleeve. The elastic slip inside the sleeve is very helpful for the air to not fall out of the bag, but also for the zipper to not rub and scratch the enclosure as you are zipping it up. It doesn't over all that much protection, but it is great for me as I can just slip it into my briefcase and off I go.