Professional and educational FlightGear users
FlightGear is used by dozens of organisations, companies and universities all over the world.
- 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.
- MathWorks provides the Aerospace Blockset libraries for interfacing FlightGear to their Simulink software.
- NASA/Ames Human Centered System Lab - 737NG full scale cockpit simulator developed by LFS Technologies. FlightGear provides visuals for four large screen wrap around displays, improved turbo-fan math models, detailed fuel system models, and extendable network interface to cockpit displays and electronics. 
- FlightGear was used by Pragolet s.r.o. in a motion platform based flight simulator of light and ultra-light sports aircraft. 
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.
RWTH Aachen research simulator
The Institute of Aerospace Engineering at the RWTH Aachen is using FlightGear to drive the cockpit and the visuals of a general aviation simulator for training and research purpose. Micro Air Vehicles are being implemented by MATLAB/Simulink flight dynamics models; all I/O-related tasks, be they required by FDM, controls or instruments, are connected over network, using FlightGear native interfaces. 
- 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.
- 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.
- The Delft University of Technology, the Netherlands used FlightGear for their ICE project. Their goals was to design, test, and evaluate computational techniques that can be used in the development of intelligent situation-aware crew assistance systems. Using methods from artificial intelligence, ICE focused primarily on the data fusion, data processing and reasoning part of these systems. 
- FlightGear is being used as the basic framework to provide the UTC Challenger Center (and hopefully other centers in the future) a low cost virtual reality computer simulation in the University of Tennessee at Chattanooga. Our simulation is using flightgear and JSBSim, specifically the shuttle module, to develop a shuttle landing simulator. Currently, we are trying to get to the point of at least contributing instructions on how to interface our virtual reality hardware with Flightgear back to the OS community.
- Department of Aerospace Engineering at The Pennsylvania State University used FlightGear primarly for its graphics engine, in advanced research programs in the areas of flight control design, advanced rotorcraft flight dynamics modeling, and near real-time acoustics simulation.