Under what condition are flight plans automatically cancelled for an IF aircraft?

When a flight plan is filed for an IFR (Instrument Flight Rules) aircraft, it remains active until certain conditions are met. One key condition for automatic cancellation is that the aircraft lands at an airport equipped with an operational control tower. This is because the tower provides established communication and monitoring which confirms the aircraft's arrival and ensures that the flight plan can be properly closed out by air traffic control.

The presence of a control tower signifies that there is a structured environment where the flight's status can be officially advised and documented, thus allowing the system to automatically cancel the flight plan upon landing. This procedure helps maintain operational safety and efficiency within controlled airspace.

In contrast, if an aircraft lands at an unapproved airport or enters uncontrolled airspace, the flight plan may not be automatically cancelled since there may not be a means of confirming the landing through communication with air traffic control. Similarly, while reaching the destination airport is an important event, it does not signify the automatic cancellation of the flight plan unless it is at a location with an operational tower. Therefore, the correct answer pertains to the aircraft landing at an airport with established air traffic control operations.