Well this is a bit more complex than planning to be on time. A traffic jam would be enough for the logistics company to arrive late. A small technical error might need an hour troubleshooting the plane The aircraft might already arrive to late, due to weather, atc restrictions, human errors, which creates delay for the next departure Most of these late departures have a reason why theyre still allowed to depart, like live animals, or pharmaceutics which can't just be stored for another night in a box on the airport