Not too sure if this is what he means but,
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Do you play continuously, meaning you allow planes to land and as soon as they are ready to leave you allow them to depart
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Or do you play in bulk, allow all planes to land, and wait until all are ready for departure. Meaning that you could have 20 inbound aircrafts and there won’t be any aircrafts taking off, ruining the flow of landing aircrafts.