...was, can you save fuel by slowing down.
Saving fuel (quantity) not cost indexes, operating costs, just fuel quantity.
The answer is, it depends.
Example, from an aeroplane I'm familiar with, the L1011, standard body aeroplane.
Generally speaking, with this aeroplane, at the proper altitude for the weight, the desired cruise speed for maximum range is, M84.
Slow down to M.82, arrive later, burn more fuel.
Speed up, say to M.86, arrive earlier, and burn slightly more fuel...but not by much.
The L1011 has a true laminar flow wing, and as such, IF you get it too slow, it will suck up fuel like a big Hoover.
Big time.
Behind an Airboos....find another level, hopefully.
