This site is being deprecated.
Please see the official X‑Plane Support page for help.
I believe X-Plane looks at other factors besides just the ramp starts--like the length of the runway vs. what the aircraft needs to take off for example.
If AI don’t seem to be using your airport or ramp starts, there are a couple art controls that you can turn on to help debug the situation. (Note you will need to set the art control then make sure the airport reloads by leaving entirely and coming back.):
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