One thing you gain is less friction. Fifty percent of the atmosphere by mass is below 18,000 feet, per wikipedia: http://en.wikipedia.org/wiki/Atmosphere_of_Ea

One thing you gain is less friction. Fifty percent of the atmosphere by mass is below 18,000 feet, per wikipedia: http://en.wikipedia.org/wiki/Atmosphere_of_Earth#Pressure_and_thickness http://en.wikipedia.org/wiki/Atmosphere_of_Earth#Pressure_an...