lightGear is an open source flight simulator for Mac OS X. The game is waiting with a lot of features and different scenarios. FlightGear pays special attention to detail which is noticeable especially in the cockpit. Everything what can be seen in the cockpit can be operated. Therefore the game is a bit complicated for a beginner and needs some training.
Anyone who even want to fly an airplane from Europe to Asia, can do this now with FlightGear - at least on the computer.