3 ms·Developing an airplane, I would guess.by krisoft 11y agoDeveloping an airplane, I would guess.rabidonrails 11y agoI heard it was the little bags of peanuts :Pfoobarqux 11y agoI meant operating costs.jonknee 11y agoYes, fuel is the major operating cost of an airliner...mnw21cam 11y agoSimilarly, for a jet engine, the fuel burned in it accounts for 99% of the environmental impact.