I prefer a (small) backpack over a shoulder/messenger bag ... a small backpack is hard to find.
So far I've tried the Swig backpack by Timbuk2. For a MacBook Air it's too large, not enough pockets, has a huge flap and about 6" of velcro to rrrrip each time you open it.
Then I tried the small Booq Mamba. As soon as it arrived I took it out of the box and the weight of it was far too much, 4lbs at least, the build and padding is overkill for a 'daypack'. So it got returned the same day.
Most backpacks are too large for a 13" computer, especially the MBA's ... then when you find a smaller backpack it's either so slim it holds the Air and nothing else or built like a tank twice as heavy as the computer.
The quest for the perfect MacBook Air backpack continues.
If you're using a backpack for your Air please post a photo or a link.
Thanks.
Do you use a sleeve on the MBA before putting it into a bag? Maybe a light padded sleeve would help an MBA fit into a backpack more snugly.. I've used North Face backpacks for a while (incredibly light and thin, but durable), but just recently ordered an 11" MBA so still trying to figure out what I want to do about carrying it around.