On longer flights, lightening the airplane by 500 pounds saves 500 pounds of fuel.
Fuel is pushing a dollar a pound.
For domestic flights, this would probably save $500 every day the airplane is in operation.
Jet-A on contract isn't any $6.70 per gallon, at least not yet.
I read that just slowing down enough to increase flight time by a couple of minutes could save millions in fuel costs.