In reference to the idea of air being transparent. it depends on what the "air" is made up from. The light produced is actually reflective light as it bounces off and scatters from the surface of whatever body it lands on first.
Oxygen has a diffraction color of blue, which is why our atmosphere turns blue when the light from the sun produces a light blue film around (or across) the earth during the day. Carbon, the predominate atmospheric element in martian atmosphere is refracted as red, which gives it a red tint.
Hydrogen is a pale yellow I think, and methane is almost white. I am not sure, but there is something somewhere that goed through the color spectrum for element gasses.
Anyway, back to the subject. Climbing stop mt everest is not only very expensive to even consdider for a local person in nepal or tibet. To have an average person go through the hassle of climbing that monster to prove the earth is round is unrealistic. A chopper flighht is expensive as hell when you are talking about the top of everest. The atmosphere is so thin that it must have no wind, lots of gas, and all sorts of other things to do it safely.
Next!