Sounds like you’re arguing against a port-run appointment system versus a system per se. When I said centrally-managed I should have said federal. It strikes me as analogous to ATC.
Planes can declare emergencies, they can divert to alternative locations, turn around for maintenance issues. And this is just IFR flights. VFR flights can take off, and once outside of controlled airspace, can just fly mostly however they want.
Your doctor takes appointments. That's a more apt analogy for what port appointments will create.
At the most congested airports slots are highly valuable, to the point where they’re often listed separately as part of an airline’s assets, and airlines will sometimes trade slots.
Many countries will fine airlines if they miss their slot time for reasons that aren’t related to emergencies or bad weather, as well as fine them for any other slot misuse such as hoarding, strategic cancellation, etc.
Now, sure, it’s not a case where if you miss the slot you can’t land or take off. The airport and ATC will always try to accommodate flights no matter what. But it usually means fairly substantial delays to avoid impacting on other take off, landing, and gate slots.
Also airlines have been given waivers since the early 2000s because the FAA realized that they were simply operating empty "ghost flights" merely to keep their slots allocated to them. So we just give them waivers every year so they don't waste fuel on this stupidity.
The ATC/FAA model is entirely inappropriate for ports.
Neither the UK nor the Netherlands choose to not enforce slot misuse. We’re not talking only about the US and the FAA as examples here.
Whether it’s an appropriate model for ports and especially truck traffic at ports is a different topic, one I’m not qualified to speak on. I was just pointing out the misconception on how airline traffic at airports works and how it’s certainly not just a first-come, first-served ad hoc model.
ATC’s role is to help manage the reshuffling when slots are missed, because there’s still finite landing and take off capacity at very busy airports.
In both cases it’s centrally managed, rather than a free for all.
I’d argue, of course, that when you file a plan, you’re requesting an appointment.
Which makes the present, in which the ILU's boss has almost turned being an asshole on the internet into an art form, politically expeditious.