Create custom AI traffic in FSX: install aircraft, build UTC schedules, compile a traffic BGL, and fix missing flights, parking or title errors.
To create custom AI traffic in FSX or FSX: Steam Edition, install an AI-capable aircraft, define valid airports and a UTC timetable in a traffic-planning tool, compile the plan as an FSX traffic BGL, and place that BGL in an active scenery folder. Test using the exact title= value from aircraft.cfg and sufficient traffic density.
What does FSX need for custom AI traffic?
FSX needs an installed aircraft, recognised airports and a valid compiled schedule before custom AI traffic can appear.
- Aircraft: The model must be in
SimObjects\Airplanesor another registered SimObject path. The traffic plan must reference the exacttitle=value from the required[fltsim.x]entry inaircraft.cfg. It does not use the texture-folder name,ui_typeorui_variation. Our AI aircraft installation and title-matching checks cover this dependency in detail. - Airports: The departure and destination must exist in FSX and be recognised by the compiler. An airport supplied only by add-on scenery may need its ICAO identifier, coordinates and elevation added to the tool’s airport data.
- Flight plans: Each schedule identifies the aircraft, airports, departure times, cruise altitude, flight rules, repeat period and activation percentage. A complete outward-and-return rotation is the safest starting point.
- Traffic BGL: FSX reads the compiled
.bgl, not the editor’s spreadsheet, database or source text. Compile specifically for FSX rather than the older FS2004 traffic format.
FSX and FSX: Steam Edition use the same basic AI traffic system. Their installation and configuration locations can differ, but the aircraft-title matching, timetable and BGL requirements are unchanged.
Is “ICE AI” part of the FSX traffic system?
ICE AI is not a standard FSX file type, timetable field or traffic setting. If the phrase means AI-controlled Intercity Express trains, that belongs to train simulation; if it means aircraft icing or anti-ice behaviour, a traffic BGL does not control it. The BGL schedules aircraft, routes, times, flight rules and traffic-percentage thresholds.
Which FSX AI traffic tool should I use?
Choose a graphical editor for a few routes, a bulk workflow for a large timetable, or a decompiler when modifying a traffic BGL that you are permitted to edit.
| Workflow | Choose it when | Main caution |
|---|---|---|
| Graphical timetable editor | You are creating a small airline or general-aviation schedule and want validation prompts. | The tool’s aircraft and airport databases may not automatically include newly installed add-ons. |
| Text or spreadsheet source | You need to manage many aircraft, routes and departure times in bulk. | A minor syntax, aircraft-number or timing error can affect several plans at once. |
| Decompiler and recompiler | You need editable source data from your own existing traffic BGL. | It cannot turn an aircraft, airport-scenery or unrelated scenery BGL into a traffic plan. |
For a practical starting point, our creator for building, decompiling and recompiling FSX traffic data supports both new plans and editable source recovery.
Can I edit an existing traffic BGL?
Yes, if it is your own BGL or you have permission to modify it. Decompile the traffic data, edit the aircraft and flight-plan sources, then compile a replacement while keeping the original file as a backup.
Remove or disable the original BGL before testing its replacement. If both remain in active scenery folders, FSX can load both schedules and produce duplicate aircraft or flights.
How do I create and install an FSX AI traffic BGL?
The most reliable method is to prove one daily return route between two stock airports before building a larger timetable.
- Verify the aircraft. Open its
aircraft.cfg, find the required livery’s[fltsim.x]section and copy the completetitle=value. Check that itssim=,model=and texture references lead to valid files or folders. Every installed aircraft title should be unique. - Select two recognised airports. Begin with stock airports that have suitable parking and working taxi routes. If an add-on airport uses a new ICAO code or exists only in replacement scenery, add the required airport record to the planning tool before compiling.
- Build a complete rotation. Add an outward leg and a return leg, leaving enough time for the flight and turnaround. FSX AI schedules use UTC, not the local time shown on an airport timetable. Weekly day numbering differs between tools, so follow the editor’s labels rather than assuming a particular number means Monday.
- Set a low activation percentage. The plan’s percentage is the minimum AI density at which it becomes eligible to run. A plan set to 50% will not appear when the relevant FSX traffic slider is below 50%. Use 1% while diagnosing a new plan.
- Validate and compile for FSX. Correct unknown airports, overlapping legs, impossible journey times and missing aircraft references. Confirm that the output is a traffic
.bgl; source text, project files and spreadsheets cannot be loaded directly by FSX. - Install the BGL in active scenery. A dedicated folder such as
...\Addon Scenery\My AI Traffic\sceneryis easy to audit, provided its parent scenery area is enabled in the Scenery Library....\Scenery\World\sceneryis also active by default but becomes harder to manage when many packages use it. Do not put traffic BGLs inSimObjects\Airplanes. - Restart FSX and test early. Load the correct simulator date roughly 15 minutes before the UTC departure. Raise both Airline traffic density and General aviation traffic density while diagnosing the plan; our explanation of what the FSX traffic sliders control helps when a schedule appears only at certain settings.
Parking is not defined by the timetable alone. The aircraft’s physical size, atc_parking_types and atc_parking_codes must work with the parking spots in the airport scenery. A valid flight plan cannot create a suitable gate, taxi link or runway connection where none exists.
Why is my custom FSX AI traffic not showing?
Most missing FSX AI traffic is caused by an exact-title mismatch, incorrect UTC timing, insufficient traffic density, incompatible parking or a legacy-format BGL conflict.
| Symptom | Likely cause and fix |
|---|---|
| No new FSX-format traffic appears anywhere | Check that AI traffic is enabled and search active scenery areas for FS2004-format traffic BGLs. A single active legacy traffic file can suppress FSX-format plans. Back up and disable or convert the identified file rather than deleting stock BGLs at random. |
| The intended aircraft never appears | Compare the plan’s aircraft reference with title= character for character, including spaces and punctuation. Check for duplicate titles and confirm that the referenced model and texture exist. |
| The flight appears on the wrong day or at the wrong time | Recalculate the schedule in UTC and recheck its repeat period. Local daylight-saving changes do not alter the UTC time stored in the plan. |
| The compiler reports an unknown airport | Add the airport’s ICAO identifier, coordinates and elevation to the compiler data. Also confirm that the same airport identifier is present in the scenery loaded by FSX. |
| An arriving aircraft disappears | The airport may have no free parking spot large enough for the aircraft. Reduce competing traffic or test at a stock airport with ample compatible parking. |
| The aircraft parks at an unexpected stand | Review its parking types and airline codes alongside the airport’s parking assignments. Codes influence stand selection but cannot override an unsuitable parking radius. |
| The aircraft remains parked or cannot reach the runway | The airport may have a broken taxi network, no valid route to the active runway or heavy congestion. Test the same plan at a stock airport to separate a scenery problem from a schedule problem. |
| Flights appear twice | The original and edited BGLs are both active, or the same schedule was compiled into more than one file. Search all enabled scenery folders and retain one copy. |
A mistake we see constantly is testing a large schedule with several unknowns at once. Reduce the project to one known aircraft, two stock airports, a 1% daily return plan and high simulator traffic settings. Once that works, add new airports, liveries and legs one at a time.
Can I use a flyable aircraft as AI traffic?
Yes, many flyable FSX aircraft can follow AI schedules, but a dedicated AI model is usually the better choice. Flyable aircraft often have more detailed geometry, textures and systems than background traffic needs, and some have contact points or animations that behave poorly under AI control.
Purpose-built AI models usually include more effective levels of detail and are less demanding when several aircraft are visible around a busy airport. For larger schedules, our guidance on balancing AI model complexity and traffic volume against frame rate explains where selective routes and efficient aircraft make the greatest difference.
The traffic BGL contains references and schedules; it does not contain the aircraft model or livery. Anyone using a shared BGL must separately have an aircraft entry with the same title= value. List those dependencies clearly, and do not redistribute aircraft or repaints unless their licence permits it.