Originally Posted by
Bend alot
I agree what you mean A Squared - but
"perform" better is why cruise is well above sea level.
Read the entire quote. Your engine does not make more power, you wings do not make more lift and your prop does not make more thrust. Yeah, as air density decreases you get a TAS gain, but only up to critical altitude or WOT. Pretty much everything else that could be considered a measure of performance decreases with altitude.