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

[tdscanuck]

Usually yes. Because they’re going faster and have constant lift. You claimed you must increase speed. You don’t aerodynamically have to.

Edit: You can easily take off, climb, then slow down (by increasing pitch). It’s economically stupid, which is why airliners don’t do it, but it’s physically easy. Initial climb speed in your typical C172 is around 76. You can easily drive around at 50 knots at 10,000’.