I fell in love with Redmaloo's laptop sleeve because of the way it folded and wrapped around your laptop, instead of a traditional sleeve that you have to slip in and slide out.
At the airport, I think this would make a world of convenient difference, since you could put it and its case down in the security bin, and then just velcro it open and closed. The dealbreaker for me, though, is the $130 price tag.
Luckily, I found a great alternative at Urban Outfitters: The Livity Wrap Sleeve — currently on sale for 20 bucks! It doesn't sport the aesthetically-pleasing, solid-colored felt of Redmaloo, but it's cute enough to do what I want it to. And it's green — made of organic cotton, hemp, and recycled polyester!