Do airliners adjust altitude for latitude?
(aviationweather.gov) Significant weather chart.

Note the numbers in boxes. They decrease as the latitude increases: 450 → 400 → 350 → 250.

Note: those values change day to day and season to season, they're not fixed.

Those are the tropopause heights. 450 is FL450, i.e., 45,000 feet at a standard altimeter reading.

This figure is very important in flight planning. Jets typically fly around this figure for optimal aircraft/engine performance.

So yes, you're right, the farther you fly from the equator, the lower you should fly. However, the following two statements are incorrect:




I'd expect that the air pressure at the top of the troposphere [be the same regardless of latitude.]


The pressure gradient is still the same. See: Why is the troposphere 8km higher at the equator than the poles?


As the altitude of an airliner increases, the angle of attack [also increases.]


As the altitude increases, so does the speed, to counter the thinner air. Until you end up in a coffin corner.



Also, for high latitude polar flights, an airline can do away with the optimal performance, because the rise in temperature helps keep the fuel from freezing, however I may stand corrected on that.