What a load of unadulterated bs.
The heavy case per hour 4% of direct operating COST per hour for flight crew.
The low case between 2.5% to 3%. Qantas is somewhere in between.
(Source QF- until labour costs became the new bonus driven doctrine)
Most aircraft cost is fixed.
Unless of course you back load all sorts of 'operating costs', to the "flight operation", whether it be duty travel, loadings so FF appear profitable for every person "sold" a seat. Engineering costs can be loaded too..How many you want to add on, so everything becomes a "profit centre" competing for Capital?
The definition applied definitely is subjective to suit the agenda of the day..As stated these days staff are the enemies.