What are airplane wheels filled with?

Answer 1

The tires on jets and turbo props are filled with nitrogen because temperature has little effect on the pressure in a nitrogen filled tire. When airplanes go past about ten thousand feet the outside air temperature starts to drop pretty rapidly. The constant up and down causes a loss of air pressure which could lead to a blow out on landing . On smaller airplanes that don't go very high in altitude some use regular compressed air because it is cheaper than nitrogen. By the way, some people have started using nitrogen in their car tires so they don't have to worry about winter and summer pressures.