Originally Posted by
old,not bold
I think that those of us who are fairly simple-minded, like me, only need to know that airliners tend to be cruised at the optimum speed for fuel economy, which is usually rather slower than maximum continuous cruise speed.
I think you may have overdone the simplification slightly.
When you introduce Cost Index into the mix, the optimum cruising speed may differ from LRC, and may also vary depending on wind conditions.