20 years is young for a cargo fleet. Passenger airlines in developed countries often aim to have an average fleet age younger than that, but the planes are buil

20 years is young for a cargo fleet. Passenger airlines in developed countries often aim to have an average fleet age younger than that, but the planes are built to fly for 20, 30, 40 years and sometimes more. And remember that the maintenance procedures, mandated by law, for commercial aircraft are kind of insane. The analogy to a car (since everything has to have an analogy to a car) would be: Every time you're about to get in the car and drive somewhere, first you do a full walk-around inspection of the exterior, then inspect all the lights, vents, wipers, horn, and so on. If anything is in less than perfect condition, you don't drive the car until it's been fixed. Every ten days, you drop the car off overnight at a garage. They do a full fluid check, tire check and rotation, alignment, lubricate everything, and if they find anything less than perfect it gets fixed before driving again. Once a month, oil change, filters replaced, new battery. If there's visible wear on the tires, replace them. Every two years or so, you pull out the engine and replace it. Every five years, you have the car completely disassembled and reassembled, replacing any part that's even the slightest bit worn or fatigued or shows any detectable amount of corrosion. If you maintained a car this way, the car would last damn near forever. This is how planes are maintained, and is why they last as long as they do.