The silver livery at Eastern was partly in response to the first gas crisis in the US during the early 1970s - taking much of the paint off of the airplanes are using the meal finish saved a bit of weight (a couple of hundred pounds or more) on each airliner and thus saved energy. Whats the saying? Every little bit helps. The metal look also freshened up Eastern's classic look. Do note that EA
's A300s never had the polished metal look, but thats another story, AA
flew their A300s is the horrible battleship gray colors until it was figured out how to polish up the metal and alloys used by Airbus.