Air Control is a free game where you are put in the position of an air traffic controller. You must direct planes to safely land without them crashing into each other. It looks simple at first, but the difficulty really ramps up (which makes for an addicting game).
Multiple game modes are available including Cargo and Mismatch. Cargo mode is a kind of puzzle game where planes must land in a certain order based on color or type. For an easier game, try Mismatch which allows the player to mix up the landing zones.
Check out the free version first, then purchase the full game ($0.97) to kill off the ads.