Some commercial products—Earth Flight Sim, Flight Pro Sim, Flight Simulator Plus, Pro Flight Simulator, Real Flight Simulator, Virtual Pilot 3D, and others—are copies of old versions of FlightGear, see Commercial redistribution. They are not endorsed by the FlightGear project.
FlightGear started as an online proposal in 1996 by David Murr. He proposed a new flight simulator developed by volunteers over the Internet as alternative to proprietary, available simulators like the Microsoft Flight Simulator. The flight simulator was created using custom 3D graphics code. Development of an OpenGL based version was spearheaded by Curtis Olson starting in 1997. FlightGear incorporated other open-source resources, including the
LaRCsim flight model from NASA, and freely available elevation data. The first working binaries using OpenGL came out in 1997.
In June 2014 Honda lawyers issued a takedown request in which it was claimed that the HondaJet model in the simulator infringes on Honda's trademarks. Subsequently, HondaJet became the first model removed from the simulator due to legal reasons.
Several networking options allow FlightGear to communicate with other instances of FlightGear. A multiplayerprotocol is available for using FlightGear on a local network in a multi aircraft environment. This can be used for formation flight or air traffic control simulation. Soon after the original Multiplayer Protocol became available, it was expanded to allow playing over the internet.
Several instances of FlightGear can be synchronized to allow for a multi-monitor environment.