Does anyone else remember the BA trial in (I think ) the mid nineties . The idea was that various aircraft set off from various airfields (globally) on EXACT times
( calculated by BA ops) and they arrived at destination in such a manner that no holding was required.
I recall having a long brief from one of the guys working on it when he visited Belfast.
The BA shuttle(their chosen aircraft in this case) would tell tower its actual time of departure and we would accomodate it.
I never heard any results but I suppose it was quietly dropped.
Is that what is meant by the OP's question?