Hey!
"Triggering an event by timer (disable if you want to trigger the event only manually)": true,
"Random time to event start": false,
"Time to event start(in seconds, minimum 900)": 3900
Please pay attention to these settings.
In this case, the event will start in 3900 seconds. But the plane will need some time to fly to the airfield, usually no more than 15 minutes. Keep in mind that the next event will start in 3900 seconds immediately after the start of the previous event, and not after its completion