Even I suggest buying the Logitech N100 cooling pad as IMO it's the best cooling pad out there... Even I have a Macbook Air and it gets hot a lot of times, but after buying this pad, it's been a lot more cooler and the Logitech is also designed really well, great ergonomics and really good to use on the lap...
Also, it really works well with the Air is cause the Air only has 1 vent at the back where it ***** the air and this pad pushes in Cold air into it and that makes a dramatic difference in performance... Example, before this pad, I couldn't watch more than 3-4 youtube video (10 minute each) as the thing would slow, but after the pad, I can easily watch up to an hour of video (still no slowdown)... The Air circulation is really great and the concave shape of it helps keep the hot air to escape and not trap beneath...
I give the logitech pad a thumbs up and a must buy for any Air user... Really quiet fan, low power consumption and keeps the degrees down....