Originally Posted by
Musket90
The published scheduled times are pushback from stand and arrival on stand. It does not include taxi times and holding in a queue for take-off which at busier airports during peak times can be anything up to 20 or 30 minutes. Some airlines deliberately publish scheduled times for departure and arrivals well in excess of the flying and taxi times it actually takes in practice which I suppose improves their punctuality statistics !
And, depending on the airline, a departure within 15 minutes, or sometimes even 30, of STD may still be classed as "on time".