Why Did Airlines Stop Polishing Their Planes?

TL;DR

Airlines switched from polished aluminum to painted planes because corrosion maintenance on unpainted surfaces costs more than the fuel penalty of extra paint weight.

Key Points

• 1.Paint saves weight but polishing saves more. A Boeing 737-700 with a polished finish uses only 11.3 kg of paint versus 81 kg for a fully painted jet — a 70 kg difference that does raise fuel costs.
• 2.Corrosion maintenance made polishing economically unviable. Unpainted aluminum requires washing, buffing, and repolishing three times per year, taking planes out of service so long that lost revenue outweighed the fuel savings from reduced weight.
• 3.Composite airframes delivered the final blow to polished finishes. The Boeing 787 and Airbus A350 have composite fuselages that cannot be polished, making it impractical to maintain two different livery systems across a mixed fleet.