Clearly the are some cultural differences in this discussion.
In this part of the world airports don't just close at the whim of the operator.
There would have to be a compelling reason for any registered or certified airport not to be available, and I would expect to see that reason stated in a NOTAM.
For example, I remember Rockhampton airport in Queensland was once closed for a couple of days because most of the runway was under floodwaters.
Sure, runways are sometimes closed at short notice because of disabled aircraft (e.g. wheels-up landing).
Generally, however, airports are open all day every day (and all night if lighting is available, and it usually is).
Also, with very few exceptions, prior permission is not required. And why should it be? Airports are part of the national infrastructure and are there to be used.
Obviously you need permission to use a private farm strip, except perhaps in the case of a forced landing.