It's nice to hear airlines are saving gas, but airplanes are limited in their ability to "hypermile."
Plane's will get their max range (i.e. mileage) when flying at a speed that maximizes their L/D (lift to drag) ratio. The L/D ratio varies with altitude and climatic conditions, but I bet most airlines know exactly where it exists on a given flight in every condition.
Fuel savings also come from modifying the rate of climb, descent, and amount of fuel carried for a flight. There are a lot of variables, but airlines are pretty restricted by regulations. Unfortunately, airlines are pretty much at the complete mercy of fluctuations in fuel prices.
I know someone on this board is at least a commuter pilot, so hopefully he'll elaborate.
- LostCause