[AceyMan]

fwiw, the old rule of thumb when I was trained is "it cost you one pound of fuel for every three that you carry", where 'cost' is in the form of increased burn (decreased efficiency).

Of course, fuel is no different than any other weight, so the same rule would apply to the revenue load (people, bags, freight)—for every three pounds it cost you one pound of fuel.

Incidentally, I've always felt ticketing should be pro-rata wrt weight. Well, where 'always' is defined as 'since I obtained my FAA dispatcher license.'

/Acey