We’ve all seen planes (if you haven’t click here) and some of us flew on them. You stand at the gate looking in admiration at the beautiful machine. Fascinated by the curves on its body and the shear size of its engines, or maybe that’s only me. But I am sure that most of us have noticed that airplanes tend to be nicely painted with the airline colours. It makes it look good, acts as marketing material and adds to the flight experience.

But there is also a technical reason why airlines paint planes, and that’s to protect the body from corrosion. As the paint fades away though, planes get repainted. And then repainted and then repainted. And after some time, believe it or not, all this paint has added weight on the plane. A Boeing 747 for example when fully painted adds 250Kg of paint (see here). So paint it only twice and you have half a ton extra on the plane. If you remove 500Kg off a 747 you can reduce carbon emissions by 0.2% OK it’s not much, but it doesn’t take much effort not to paint a plane.

Or does it? In order to protect the plane against corrosion once the paint is gone, we must polish it. If we polish our 747 and put some airline logos on it we end up with only 25 Kg of paint on it, so quite a good saving.

Now think about those airlines which charge you a lot of money for that extra kilogram you have in your bag. Every extra kilogram burns some extra fuel and that costs a lot of money. And since the major cost for airlines is fuel, it pays to take 250Kg off your plane. So if I was a CEO of an airline, you would hear me shouting “Wait! Don’t paint that plane.”