VIPs are by definition rare. I don't want to make you think they're doing a bunch of these every day. It's probably every once in a while.

I also don't think slot controls are always initiated when a flight is still at its originating airport. I think a lot of us have been on flights that left on time then in mid-air were delayed due to congestion. Because they are often done on the fly, I don't think it's hard to move a flight up in line, just that the reason is a little more elitist than the normal weather or such.

Those are all the relevant details I have. I don't think the name of the airline/the airport/ the nature of this VIP are germane to this discussion.