It has specific builds for a variety of different operating systems including Microsoft Windows, macOS, Linux, IRIX, and Solaris.

Its flight dynamics engine (JSBSim) is used in a 2015 NASA benchmark to judge new simulation code to the standards of the space industry.

[6] FlightGear incorporated other open-source resources, including the LaRCsim flight dynamics engine from NASA, and freely available elevation data.

Around that time, the graphical front end "FlightGear Launch Control", also known as "FGRun", was replaced by a hard-coded Qt launcher.

[8] FlightGear's source code is released under the terms of the GNU General Public License and is free and open-source software.

[9][10][11] Forces experienced by a flying aircraft depend on the time-varying state of atmospheric fluid flow along the flight path - the atmosphere being a fluid that can exchange energy, exchange moisture or particles, change phase or other state, and exert force with boundaries formed by surfaces.

Fluid behaviour is often characterised by eddies(Videos:aircraft, terrain) or vortices on varying scales down to the microscopic, but is harder to observe as the air is clear except for moisture phase changes like condensation trails or clouds.

Forces experienced at any point along a flight path, therefore, are the result of complicated atmospheric processes on varying spatial scales, and complex flow along the craft's surface.

Atmospheric water is modeled by FlightGear ranging from state changes such as condensing into cloud or haze layers, along with energy provided from latent heat to drive convective fluid flow, through to precipitation as rain droplets, snow, or hail.

[16][17] FlightGear also has a less physically accurate model that uses METAR weather updates of differing frequency, designed for safe operation of aerodromes, to dis-continuously force atmosphere based on attempted guesses of processes that are fundamentally constrained by the closeness or density of observation stations, as well as the small-scale, limited, rounded off, non-smoothly varying, and need-to-know precision of information.

[20] A model of the observed variation in the Earth's complex magnetic field, and the option to simulate, to an extent, the propagation of radio wave signals due to interaction with different types of terrain, also exists in FlightGear.

[25] Flight characteristics are preserved despite low frame rate, as JSBSim physics are decoupled from rendering and tick at 120 Hz by default.

For all interactions with the simulator, it allows people to speed up uneventful parts, and gain more experience (decisions and problem solving).

FlightGear is able to support high time accelerations by allowing parts of the simulation to run at different rates.

This allows saving of CPU and GPU resources by letting unimportant parts of the simulation, like visuals or less time-sensitive aircraft systems, run at slower rates.

[39][37][38] FlightGear is able to render specified historical accumulation levels of water and snow accounting for flatness on the surfaces of for both terrain and buildings.

[13][37] FlightGear is able to render day/night visuals of Earth from orbit at high detail with scattering due to clouds, dust, and moisture, as well as effects such as lightning illuminating storm cells.

Orientation cues in cockpit are provided by changing colour of light from Sun, Earth, and Moon for craft such as the Space Shuttle.

The gradual transition in lighting for spacecraft, between upper and lower atmosphere regimes, is handled by dedicated rendering code.

FlightGear is capable of rendering a variety of volcanic activity of different intensity that, from v2019.2, responds to the windfield, as well as smoke.

[51] Games journalist Tim Stone, in his simulation column The Flare Path, criticized the practice of third-parties attempting to profit from the work of community volunteers to the project, pointing to deceptive practices of stealing media available online from other sims to misrepresent VirtualPilot3d, as well as highlighting allegedly fake customer testimonials.

[52] Following up in 2018, Tim Stone wrote a second column in which he again criticized the "ethical standards" and "extraordinary willingness to lie in the pursuit of sales" displayed by the advertisements for another game which used screenshots from FlightGear.