MacBook Air takes an eternity to come out of sleep
sudo pmset -a hibernatemode 0 should disable "smart sleep" mode.
Well, the MacBook Air goes one step further than sleep into what Apple calls Standby mode. This is a deeper form of sleep that uses much less power and takes a bit longer to start up again. This is how Apple achieves the advertised 30 days on standby.
http://www.apple.com/macbookair/features.html#longlasting