Learn how AI traffic flight plans schedule aircraft, routes and times, how simulators spawn flights, and why traffic may fail to appear.
AI traffic flight plans are schedules that tell a flight simulator which virtual aircraft to use, where it should depart and arrive, when the flight runs, and usually its cruise altitude and flight rules. The simulator reads that data, spawns the aircraft before departure, then lets its AI and ATC systems fly the route.
What is stored in an AI traffic flight plan?
An AI traffic flight plan is closer to an airline timetable than the .PLN route loaded into the player aircraft. A typical scheduled plan contains:
- an aircraft type, model or database reference;
- departure and destination airport identifiers;
- departure and sometimes arrival times;
- a flight number or callsign;
- IFR or VFR flight rules;
- a cruise altitude;
- a repeat period, operating days or linked sequence of legs;
- a traffic-density percentage or priority in systems that support one.
Not every format stores all these fields. In classic Microsoft simulators such as FSX, schedules are commonly compiled into a traffic BGL, while the aircraft model and livery remain separate. Newer traffic products may keep schedules in their own databases and inject aircraft while the simulator is running.
How does the simulator turn a schedule into a flight?
The traffic engine matches each eligible schedule to an installed aircraft and then manages the flight from parking stand to arrival.
- Select the schedule: The engine checks the simulator time, operating period, traffic setting and any package-specific filters.
- Resolve the aircraft and airports: It looks for the assigned model and valid departure and destination airport records.
- Spawn the aircraft: The aircraft normally appears at a suitable parking position several minutes before departure.
- Operate the flight: AI and ATC logic handle pushback, taxi, runway selection, take-off, en-route navigation, descent and landing.
- Complete the cycle: After arrival, the aircraft may remain for its next leg, be reused by the traffic engine or disappear.
The schedule does not control every movement. Airport scenery supplies parking positions, taxi links and runway data, while weather, runway configuration, congestion and ATC can delay or reroute the aircraft.
In many classic systems, the traffic-density slider acts as a filter rather than simply reducing every airport proportionally. A plan assigned a higher threshold will not run until the slider reaches that level. Other engines instead impose a maximum-aircraft limit.
Do AI flight plans contain waypoints and airways?
Most traditional AI schedules specify the endpoints and basic operating details, not a complete chain of waypoints. The simulator generates the usable route and applies its own navigation and ATC logic.
This is why editing the flight plan loaded into your cockpit does not normally change AI traffic. Some external traffic engines can use detailed routes, procedures or tracking data, but those capabilities belong to that engine rather than to every simulator.
How are scheduled AI and live traffic different?
Scheduled AI replays prepared timetables, while live traffic converts real-world tracking or service data into simulated aircraft.
| Traffic type | Source | Typical behaviour |
|---|---|---|
| Scheduled AI | Compiled plans or an add-on database | Repeatable and available offline, but only as accurate as its timetable |
| Live traffic | Real-world flight and position data | Reflects actual operations but depends on data coverage and an active service |
| Generated traffic | Rules, demand or randomised schedules | Provides variety without reproducing a precise airline timetable |
Microsoft Flight Simulator can combine built-in traffic with external injection methods. Our explanation of how real-world flights are injected into MSFS 2020 shows how that differs from a traditional compiled schedule.
Why is a scheduled AI flight not appearing?
Missing traffic usually means the schedule failed its time, density, aircraft, airport or compatibility checks.
- Wrong simulator time: AI aircraft are normally created before departure, not after the scheduled time has passed. Set the session several minutes before the flight when testing.
- Traffic setting too low: Raise the relevant airline or general-aviation density setting temporarily to determine whether the plan is being filtered.
- Missing aircraft assignment: A changed aircraft title, unavailable model or broken add-on reference can leave the schedule with nothing to spawn.
- Invalid airport identifier: Renamed, replaced or incorrectly coded airports can break one or both ends of the leg.
- No suitable parking: The airport may lack a free stand with the required radius, parking type or airline code.
- Wrong traffic format: Compiled schedules are not universally interchangeable between simulator generations. In FSX, an old FS2004-format traffic BGL can prevent newer-format traffic schedules from displaying.
- Injector not running: Live and database-driven add-ons may require a separate process or plugin; their flights do not exist merely because aircraft models are installed.
A mistake we see constantly is replacing aircraft files without updating the schedule’s model reference. The livery can be perfectly installed yet remain invisible because the plan still points to the previous aircraft entry.
What makes an AI traffic schedule realistic?
A believable schedule must fit the aircraft’s performance, airport capacity and the time needed between legs.
- Allow enough time for taxiing, the flight itself and turnaround at the destination.
- Use sensible cruise altitudes for the aircraft and route length.
- Add return or positioning legs so the aircraft can continue through a logical cycle.
- Avoid sending large aircraft to airports without suitable runways or parking.
- Stagger departures instead of placing an entire timetable at the same minute.
Unrealistic block times can make an aircraft depart late, skip a leg or fail to complete its repeating cycle. Congested airports amplify the problem because AI traffic must share taxiways and runways.
Can I create or edit AI traffic flight plans?
Classic FSX traffic can be created by defining the aircraft, airports and legs in source data, then compiling the result into a traffic BGL.
Our walkthrough of the complete FSX schedule and BGL workflow covers the relationships between those components. An FSX utility for creating and editing AI schedules can also reduce formatting mistakes.
Keep the source schedules and back up the compiled file before changing anything. Compiled BGL files are output files, not ideal master copies, and tools intended for one traffic format may create files that another simulator cannot read correctly.