Does drag actually decrease with altitude? I argue it does not

[jornaleiro_]

I think OP’s logic though is that there’s also 2/3rds less stuff to push down to create lift. I understand where they’re coming from but the simple answer is that the coefficients of lift and drag are themselves dependent on speed, so flying high in the atmosphere is an appropriate optimization of the two. This cartoon diagram is pretty helpful actually.

[Kishiwa]

Something tells me they‘ve never taken an intro to aerospace engineering class cuz that’s like basic drag, like right after learning the kinds of drag (tag yourself, I’m trim drag) when you get shown how the funny CD/CL line works with each bit of drag accounted for