Power is also limited by air density (the degree of this limitation depends on the engines for the particular aircraft). So it's a double-whammy. Hot/thin air r

Power is also limited by air density (the degree of this limitation depends on the engines for the particular aircraft). So it's a double-whammy. Hot/thin air raises the power required while reducing the power the system is able to produce. This might be offset by shedding weight (reducing the power needed since you're lifting less), but there are limits there as well since a lot of things are either bolted on or necessary for the mission.