Professional and educational FlightGear users
FlightGear is used by dozens of organisations, companies and universities all over the world.
Todd Moyer of Aeronautical Radio, Incorporated (ARINC) used FlightGear as part of an effort to test and evaluate Flight Management Computer avionics and the corresponding ground systems. Certain capabilities of the Flight Management Computer are only available when airborne, which is determined by the FMC according to data it receives from GPS and INS sensors.
They wrote additional software that translates the NMEA output of FlightGear (including latitude, longitude, and altitude) into the ARINC 429 data words used by GPS and INS sensors. These data words are fed to the Flight Management Computer. the position information from FlightGear is realistic enough to convince the FMC that it is actually airborne, and allows ARINC to test entire `flights' with the avionics.
- University of Illinois at Urbana Champaign. FlightGear is providing a platform for icing research for the Smart Icing Systems Project. 
Simon Fraser University, British Columbia Canada. Portions of FlightGear were used in simulation to develop the needed control algorithms for an autonomous aerial vehicle.
- Iowa State University. A senior project intended to retrofit some older sim hardware with FlightGear based software.
- University of Minnesota - Human Factors Research Lab. FlightGear brings new life to an old Agwagon single seat, single engine simulator.
- Aeronautical Development Agency, Bangalore India. FlightGear is used as as the image generator for a flight simulation facility for piloted evaluation of ski-jump launch and arrested recovery of a fighter aircraft from an aircraft carrier.
- Veridian Engineering Division, Buffalo, NY. FlightGear is used for the scenery and out-the-window view for the Genesis 3000 flight simulator.
- The Intelligent Robotics Group at the University of Wales, Aberystwyth, UK is using FlightGear as part of their aerobot research to design aerial vehicles that can operate in the atmosphere of other planets.