Originally Posted by
number_6
Almost all J seats take up more square footage than 2 Y seats.
35...40 inches pitch where Y has 32 inches and 4 abreast where Y has 6 or 5 abreast, or 6 abreast where Y has 7 or 8 abreast, is not double the floor area. So you cannot say almost all.
Originally Posted by
number_6
It varies a lot by airline. Also weight is more of a cost factor than space; the more complex J seats weigh hundreds of pounds. F seats can be equal to as many as 10 Y seats (e.g. the new CX F suite).
But hauling empty airframe and air burns most of the fuel needed to haul loaded aircraft.
Originally Posted by
number_6
As for catering costs, these are easily found on the web (try google!). What airlines spend for meals varies tremendously, but most US airlines spend USD 35 to 50 for trans-Atlantic F/J flights, while the top airlines such as CX and SQ spend over USD 150 for F catering. They also use wines costing over USD 100 per bottle. I would guess the top-end food/wine cost runs about USD 400 per flight, while the bottom end (US Y catering) is about USD 10. Or about 40:1 ratio.
Do not forget meal choices, either. How much of the business and first class catering is actually used, and how much is carried in case someone wants it, then thrown away since premium passengers would regard it as stale?