shockwave1973,
Just to add a footnote to the preceding wise comment, you may note that as an aircraft increases Flight Level in accordance with optimum step climb, that the Mach Number remains relatively constant (within a very small margin). Naturally, at a constant Mach Number with increasing Flight Level, CAS (and importantly EAS) reduces.
Thus, the High Speed Polars remain quite constant, whilst the Low Speed Polars reduce, leading to overall reduction in drag.
411A, it's not Ebonics, it's cell-phoneese!!! Dun U no dat! Every time that a young Prooner posts (well almost every time) I have to get my kids to translate it for me
Ti Tien,
Old Smokey (with apologies to shockwave1973 for poor anglisitasion of Chinese)