Do they wait until all aircraft have landed before winding up an airline? This BBC article suggests that any announcement about winding up Thomas Cook will wait until late at night and all its planes are on the ground (I guess they don't fly long haul distances?) before an announcement is made about bankruptcy.

What is the significance of this? Surely no airport would turn away an aircraft that needed to land?

Is it an insurance thing?

How do airlines which never have all their planes on the ground get wound up?
The article speculates based on a single precedent:


  It's likely (looking at the precedent of Monarch's collapse) that any announcement about that will be made late at night, once all planes are on the ground.


But evidently that's not entirely the case. Thomas Cook ceased trading at 0109 UTC of the 23rd, with some of its planes still in the sky:


(Flightradar24) Showing only TCX callsigns.

As you can see, some of them are long-haul returning from USA. I also could not correlate last departure time with the announcement. The latest I found was at 1131 UTC (MT2643 from Orlando to Manchester).