Originally Posted by
GordonR_Cape
The takeoff ground speed, engine power, and pitch attitude in the climb, would probably all have been higher, to compensate for the lower air density (about 80% of sea level pressure). Not a pilot, but I can't think of any other differences, once they were airborne.
Less oxygen coming to the brain also. May be negligible, especially as they were used to this altitude, not higher than cabin altitude in flight.