The air is rare and thin

been looking for days now and haven't found any reference to this. understand it implies a priviledged club or neighborhood. maybe this is a badly bastardized quote but it's all I can remember. grateful for any help.

It is a fact of physics that as you start leaving the earth's atmosphere the amount of oxygen molecules, AKA air, decreases.

Anything "up", whether it be your moving in a spaceship out of the earth's atmosphere or your being in a special neighborhood or your belonging to a special club or a socio-economic level, brings you to an area where the "air" is rare and thin.