Originally Posted by JohnWM
. Could you share your experiences and recollections with me about just how WARM that upper deck of the B747-400 becomes once aloft in warm/hot weather?
At roughly 35,000 feet (if that meets your definition of "aloft") the outside air air temperature is around -10 degrees celsius.
On the 747-400, you will, as on every other plane, be alternately too hot and then too cold in no particular order regardless of where you are seated. Enjoy the flight.