The reason for this must be obvious, although quite insufficient.. .Most pax do not know or care about STAs slot restrictions, stand availability or fuel burn. The point is that delays while on the ground (at either end of the flight) are perceived to be the fault of the airline,but delays in the air are easily palmed off onto ATC.. .Airlines like to promote an image of an outfit where you walk on to the plane take off, fly, land and then get off. If you have to fly for a bit longer, that's ok cos you can blame ATC and most pax won't mind. If you sit on the ground for a bit longer pax get unhappy.. .Airlines will have done market research showing the truth of this and that's how these edicts find their way into the system, although I expect it's quite hard to get someone to admit it.. .Should they come clean and simply explain to the pax that, whilst they may not like sitting on the ground, it produces a lot less noise and expensive hot gas than holding?