FlightGear vs FSX on realism, aircraft, scenery, add-ons, performance and setup. Find out which flight simulator is the better fit for you.
Microsoft Flight Simulator X (FSX) is better for Windows users who want built-in lessons, missions, menu-driven ATC and a huge legacy add-on catalogue. FlightGear is better for anyone wanting a free, open-source simulator on Windows, macOS or Linux. Neither is inherently more realistic: the chosen aircraft's quality matters most.
FlightGear vs FSX at a glance
| Category | FSX | FlightGear |
|---|---|---|
| Cost and licence | Commercial, closed-source software | Free and open source |
| Desktop platforms | Windows | Windows, macOS and Linux |
| Getting started | Guided lessons, missions, flight planning and menu-driven ATC | Usable launcher, but individual aircraft require more documentation and setup |
| Aircraft | Cohesive but dated default fleet; enormous legacy add-on catalogue | Broad community selection with substantial differences in quality and maintenance |
| Flight modelling | Legacy engine that sophisticated add-ons can extend considerably | Supports systems including JSBSim and YASim; accuracy is aircraft-specific |
| Scenery | Dated default world backed by many established scenery packages | Global scenery through automatic downloads or local packages; detail varies by region |
| ATC and structured content | Stronger integrated package, although its ATC is scripted | ATC and multiplayer facilities exist but are less unified |
| Customisation | Large freeware and commercial ecosystem | Direct access to aircraft files, configuration and source code |
| Main limitation | Old 32-bit architecture and legacy Windows compatibility problems | Uneven content quality and a more technical workflow |
For somebody starting from nothing, FlightGear offers the better value and broader desktop support. FSX remains the stronger packaged experience, especially when its missions, familiar interface or a particular FSX add-on is the reason for choosing it.
Are FSX and Microsoft Flight Simulator the same thing?
FSX is Microsoft Flight Simulator X, an older Windows release; it should not be confused with Microsoft Flight Simulator 2020 or Microsoft Flight Simulator 2024. That distinction changes the comparison substantially.
If “Microsoft Flight Simulator” means MSFS 2020 or 2024, Microsoft offers far newer graphics, streamed world data, more contemporary weather presentation and an integrated console experience. FlightGear still wins on price, open-source access, Linux and macOS support, and freedom to inspect or modify the simulator. MSFS 2020 is on PC and Xbox, while MSFS 2024 is on PC, Xbox Series X|S, PlayStation 5 and PS5 Pro.
Modern visuals do not guarantee accurate aircraft systems, so aircraft quality still needs to be assessed separately. Our full comparison of FlightGear with modern Microsoft Flight Simulator covers that different buying decision.
Is FlightGear realistic compared with FSX?
FlightGear can be highly realistic, but it is not uniformly more realistic than FSX. Both platforms range from simple aircraft intended for casual flying to carefully developed models with credible performance, cockpit procedures and systems.
FlightGear aircraft can use flight-dynamics systems such as JSBSim and YASim. These are capable tools, but the result is only as good as the geometry, mass distribution, engine data, aerodynamic coefficients and control logic supplied by the aircraft developer. An attractive 3D cockpit is not proof of an accurate flight model.
FSX has the same variation. Its default aircraft favour accessibility, while advanced add-ons can replace or extend gauges, systems and behaviour through custom code. A strong FSX add-on can therefore outperform a weak FlightGear model, and the reverse is equally possible.
To judge either simulator, compare measurable behaviour with the real aircraft's operating data:
- Take-off distance at a known mass, temperature and pressure altitude
- Climb rate at the specified speed and power setting
- Cruise speed, fuel flow and engine indications
- Stall speed and behaviour in a documented configuration
- Trim response, flap effects and control authority
- Electrical, fuel, hydraulic and navigation-system logic
Control setup can spoil an otherwise credible aircraft. Duplicate axis bindings, an uncalibrated joystick or a noisy rudder input often cause twitchiness wrongly blamed on the flight model. Apply a small dead zone only where hardware noise requires it, rather than masking the problem with extreme sensitivity settings.
For a closer examination of these limits, see our assessment of FlightGear's flight dynamics, systems, weather and scenery realism. Neither ordinary consumer installation should be treated as an approved flight-training device.
Which has better graphics, scenery and aircraft?
FSX has the deeper legacy add-on catalogue, while FlightGear has the more open and adaptable content system. Neither simulator's default world offers the visual consistency of Microsoft Flight Simulator 2020 or 2024.
FSX builds its world from terrain mesh, landclass, textures, autogen, airport files and layered scenery packages. Its defaults look dated, but a well-developed airport and surrounding region can still be convincing. The cost is that high-resolution textures, dense autogen, AI traffic and a complex aircraft all compete for the application's limited address space.
Compatibility labels matter with FSX add-ons. Software designed for boxed FSX, an installation with Acceleration or FSX Steam Edition may use different installers, paths or supporting modules. Check the stated edition before installing anything; the range of FSX freeware aircraft, scenery and utilities in our library also shows why the simulator retains a loyal following.
FlightGear can fetch terrain through TerraSync or use scenery stored locally. Coverage is global, but object density, airport buildings and terrain detail can change sharply from one location to another. A first visit may also look incomplete while scenery tiles are still being downloaded.
Aircraft quality varies even more than scenery. Some FlightGear projects offer detailed startup procedures and systems, while others are old, incomplete or incompatible with a newer simulator release. Start with a maintained model and consult the aircraft-specific instructions; our selection of well-developed FlightGear aircraft and add-ons worth trying helps avoid judging the whole simulator by a weak download.
Is FSX easier to use than FlightGear, and is it still worth playing?
FSX is easier during the first few hours, and it remains worthwhile when its structured content or a specific add-on matters to you. Lessons, missions, AI traffic, flight planning and ATC are presented as parts of one coherent package.
The interface looks old, and installation can become less friendly once legacy add-ons are involved. A mistake we see constantly is installing several aircraft, scenery packages and utilities together, then having no way to identify which one caused a crash. Add and test one package at a time, keeping edition compatibility in view.
FlightGear's launcher makes basic choices such as aircraft, airport, weather and scenery accessible. The extra difficulty appears after loading: one aircraft may start ready to fly, another may be cold and dark, and a third may depend on controls or procedures explained only in its own documentation.
FSX also provides the more approachable built-in ATC, but it is scripted and can issue awkward or unrealistic clearances. FlightGear has ATC-related and multiplayer features, though they are less consistent as a single-player teaching system. Neither should be used as authoritative operational guidance.
Which runs better on an older PC?
FSX is usually more predictable at modest default settings, but its age does not guarantee smooth performance. It relies heavily on processor performance, while dense autogen, AI traffic and complex cockpit gauges can reduce frame rates even when the graphics card is not fully occupied.
FlightGear performance changes substantially with the aircraft, rendering options, shadows, clouds and scenery. A detailed airliner can run far more slowly than a simple general-aviation aircraft, making simulator-wide benchmark claims misleading.
Use this sequence to find the actual bottleneck:
- Establish a baseline: load a simple aircraft at an uncomplicated airport with clear weather and default scenery settings.
- Check the controls: remove duplicate bindings and watch for a noisy axis causing continuous control-surface movement.
- Add one source of load: test the intended aircraft before increasing scenery complexity, traffic, clouds or shadows.
- Repeat at the problem airport: if performance collapses only there, scenery density or duplicated airport packages are more likely than the aircraft.
- Watch the failure pattern: an FSX crash late in a flight near complex scenery often points to address-space exhaustion rather than a lack of system RAM.
Do not move every graphics slider at once. Changing one category at a time produces a useful diagnosis and prevents unnecessarily poor image quality.
What usually goes wrong, and how do you fix it?
| Problem | Likely cause and practical fix |
|---|---|
| FSX reports that memory is exhausted or closes near a detailed airport | FSX is a 32-bit application with a finite per-process address space. Extra physical RAM does not remove that ceiling. Reduce large textures, autogen, AI traffic and scenery complexity, then disable overlapping scenery packages. |
| An FSX add-on installer cannot find the simulator | The installer may expect a different boxed or Steam Edition path or registry entry. Confirm that the add-on supports the installed edition and point it to the actual FSX directory. Do not solve this by placing unknown DLL files in Windows system folders. |
| FSX shows duplicate runways, buildings or airport objects | Two scenery packages may contain airport or AFCAD files for the same location. Disable the duplicate airport definition and check scenery-layer priority rather than deleting unrelated texture files. |
| FlightGear shows ocean, flat terrain or sparse scenery | TerraSync may not have completed the tile download, or its cache path may not be writable. Check the scenery setting, network access, free disk space and cache location, then allow the first download to finish. |
| A FlightGear aircraft will not start or has missing systems | It may require a full cold-start sequence or have been built for another FlightGear release. Read its documentation and test a known maintained aircraft before reinstalling the simulator. |
| Controls are excessively sensitive in either simulator | Calibrate the device, remove duplicate elevator, aileron, rudder and throttle assignments, and add only enough dead zone to suppress hardware noise. |
Can FSX add-ons be used in FlightGear?
FSX add-ons cannot normally be installed directly into FlightGear. The simulators use different aircraft structures, flight-dynamics definitions, gauge systems, scenery formats and supporting code.
A developer may be able to rebuild or convert source assets when the licence permits it, but copying an FSX aircraft or scenery folder into FlightGear will not work. Ownership of an FSX add-on also does not grant permission to redistribute its models, textures or sounds in another simulator.
Should you choose FSX or FlightGear?
- Choose FSX if you use Windows and want guided lessons, missions, menu-driven ATC, a familiar interface or access to a particular legacy aircraft or scenery package.
- Choose FlightGear if you want a free, open-source flight simulator, need native macOS or Linux support, or enjoy modifying aircraft, configuration and simulator code.
- Judge by the aircraft if procedural or aerodynamic realism is your priority. Test the exact model you intend to fly rather than assuming one simulator is always more accurate.
For a new user choosing only between these two, FlightGear is the better-value platform and FSX is the better self-contained package. FSX still makes sense when its structured content or established add-on ecosystem is central to the decision; otherwise, FlightGear avoids paying for and maintaining an ageing 32-bit simulator.