Airline travel is the most obvious place in our society where egalitarianism is thrown out the window and where you are openly fawned upon or frowned upon depending on your status. It begins at the gate where business and 1st class board first and continues right through the entire flight process. The worst in my opinion is curtaining off the upper classes from the lower classes and not allowing the lower classes to cross and use the lav. 
It's like being in steerage on a ship.