Originally Posted by
jeet
ATC absolutely doesn't care but plays it somewhat democratically and allocates slots to airlines at busy times.
Then its up to the airlines to decide which flights get a hold and which ones can still take off on time and keep the landing slot.
Have seen at DFW where AA and AS flights into SEA were scheduled to leave at around same time and AA took off on time but AS took an ATC delay. On that day some other AS flight into SEA took priority over the one leaving DFW
Exactly, During a published GDP, airlines are allowed to cancel/substitute their own flights.
Por ejemplo: let’s say we have hourly service from XXX-YYY. YYY goes on a GDP with average two hour delays. The airline SOC could cancel two of the flights and substitute all the others to be back ontime (essentially taking the slots of the earlier cancelled flights). It doesn’t always work out exactly like that (sometimes the AAR changes due to weather), but it is a very valuable tool for system ops. We utilized it a lot in the mid 2000s when I worked in an SOC. Unfortunately load factors are a lot higher across the board these days, so I’m not sure how much value that tool has anymore.