Name: FlightGear

Platform: Windows, Mac, Linux

Download Link: www.flightgear.org

Scenery Download: scenery.flightgear.org

Manual Download: mapserver.flightgear.org/getstart

Source code: flightgear.org/download/source-code

Description:
FlightGear is a free flight simulator. FlightGear allows for networking. Several instances of FlightGear can allow for a multi-monitor environment. Some commercial products like Flight Simulator Plus, Pro Flight Simulator, Flight Pro Sim, and Earth Flight Sim are copies from FlightGear. All official aircraft can be downloaded individually and updated within FlightGear itself.

System Requirements (Recommended):
64-Bit QuadCore Processor
8 GB Free RAM
5 GB Hard Drive Space (Minimum) 80 GB for Everything
A 3-Button Mouse with Scroll Wheel
3D Video Card That Supports OpenGL 2.1
SSD if Possible

Supported Video Cards: wiki.flightgear.org/Supported_Video_Cards