Having been a fan of Firemint's Flight Control for sometime, I was intrigued when I caught a glimpse of indie title Air Traffic Control.
Instead of trying to simplify the art of managing, taxing, handing off and landing a sky full of planes, ATC mimics the complexity of the task. In the game you have to pay attention to airport codes, altitudes, speeds, hand-off points, and runway directions.
The $2 iPad game sounds daunting, but surprisingly, it's also kinda fun. Despite some odd wording in iTunes, ATC is only available on the iPad.