[ Thanks to Dart for
this link. ]
“Founded in 1997, FlightGear is developed by a worldwide group
of volunteers, brought together by a shared ambition to create the
most realistic flight simulator possible that is free to use,
modify and distribute. FlightGear is used all over the world by
desktop flight simulator enthusiasts, for research in Universities
and for interactive exhibits in museums.“FlightGear features more than 400 aircraft, a worldwide scenery
database, a worldwide multi-player environment, detailed sky
modelling, a flexible and open aircraft modelling system, varied
networking options, multiple display support, a powerful scripting
language and an open architecture. Best of all, being open-source,
the simulator is owned by the community and everyone is encouraged
to contribute.”