Freds 73 Scamp restore on a budget

It's pretty simple actually. Everything has weight savings on an aircraft. The more it weighs total, the less useful load weight it can carry. Think about the weight of a gallon of paint and a gallon of primer, times however many gallons of paint and primer just to paint an aircraft. That's the main reason they strip them to bare metal when repainting them.

The main reason American Airlines had polished silver jets and just had the wings painted grey and of course the red, white, blue stripes on the fuselage. It saved weight having polished skin instead of paint.

Imagine how many gallons of paint and primer to paint an entire Boeing 747 400 series. Now imagine the weight of all that paint and primer.

Some aircraft when fully loaded with people, baggage, and full tanks of fuel, exceed their landing weight until enough fuel is burned off while flying. These aircraft are equipped to jettison fuel overboard in the event of a major issue requiring them to land right after takeoff. So they dump fuel to get the weight down within landing limit so they can do an emergency landing.