It sounds like a contradiction. At 30,000 feet (cruising altitude), the air outside the plane is freezing cold (around -50°C). So, why do electronic power supplies often overheat and burn out when flying high? The answer lies in the density of the air. Down here at sea level, air is thick. When a cooling fan blows air over a hot chip, that thick air grabs the heat and carries it... https://cometenvirons.com/