Official Google Plus page of FlightGear Flight Simulator. Please note that our forum is the primary location to get support: forum.flightgear.org
The FlightGear flight simulator is a sophisticated, realistic
flight-simulator, created entirely by volunteers, and released as free,
open-source GPL software, available for download here. FlightGear has a
graphical user interface realistic enough for real-life pilot training,
and mathematical flight models accurate enough for serious flight
training and scientific research. FlightGear's free and open license also makes it great for educational exploration, or just for fun.
FlightGear can be expanded and improved by anyone interested in
contributing. The complete project source code is available via Git,
licensed under the GNU General Public License. FlightGear's open
architecture encourages the exploration of a wide variety of flight
simulator concepts, and has inspired a number of related projects.