Push and hold had been in for some time when I retired 16 yrs ago .
A very efficient idea .
Push on time [ hopefully] , delay to take off the attributed to Air traffic Control ... Those who manage can then hopefully improve things .
Gate freed up for arrivals ... How many times had we busted a gut to get in on time , then a long wait for a gate !
Pushback crew and tug freed up , again how many waits for a tug !
Gate staff freed up , and no herding cats when boarding delayed !
Park up somewhere near take off holding point , shut down . No more fuel use than on the gate with APU working ...... Slot comes forward [ It does happen } , ready to launch in 2 mins ..
USA , does not seem to do it [ plenty of gates ? ] . Certainly not for international flts ....... If V. strong tailwind and flight time so short as to arrive before airport open ...
Then delay is taken on the ground at gate in US.
Africa , Mid East , Far East ... go on time , else you won't get your place or flight level in the stream of a/c heading Europe way .
JFK congestion ... taxi up one runway down another , repeat .. Ops had some idea of taxi times , and thus taxi fuel planned . Aer Lingus Ops excellent , BA okish ..
Personal best 2hrs 11mins .... and yes she did taxi ok with 2 shut down no matter what the book said [ dare not try with 3 shutdown ] ,.. Others had to return to gate to refuel ...... That really upset ATC , trying to get a few from the outbound stream and weave them back to terminal !
Yes the on time performance figures are better , but all the above reasons out-way that .
rgds condor .