"767-300ER consumes 1,600 gallons of fuel for each hour in flight" according to one link, to give you some back-of-envelope math.

Looks like in the US, Jet A costs roughly $4/gal (I'm sure airlines pay less, due to volume and such) but that means the plane is burning $6500/hr in fuel.

Very rough guesses on labor: figure the two pilots are making $100k/year, that's $100-200/hour just for them. Cabin crew I'd guess are 50k/year, google says 7 of them, so that's $350-700/hour there (figures are doubled because I seem to recall the true cost of an employee is usually twice their salary?)

So very very roughly, fuel costs are 10x labor costs