fuselage

But the cost of fuel doesn't increase with the volume of the payload because the fuselage is statically sized.

A hole in a plane's fuselage or wing doesn't mean that everyone dies.

Then why the fuselage of an airplane is smooth?

The diameter of the fuselage is so much bigger than the soda can that the actual stress on the walls are roughly only 1.5x bigger on the soda cans.

More important than pressure differences, is the circumferential stress on the fuselage/can, which is what the walls are actually withstanding.

The Falcon already has 9 engines at the bottom, but they're clustered closely together to fit under a narrow fuselage.

There's been a decent amount of research that the upper portions of the fuselage are more durable locations for engines.

That, in turn, led to an unusually fat fuselage that is so high it completely obstructs the rear of the canopy.

Remember that wings on commercial jetliners are designed to eat an entire disintegrating jet engine in order to protect passengers in the fuselage.

I mentioned nothing about UAVs or solar power (which is only possible with an enormous wing/fuselage ratio).

Halfway down the interior fuselage you can seen the terrifyingly small cable pulleys that transfer pilot commands laterally to the wing control surfaces.

Oh, when I said 'part of a single fuselage' boosters was what I had in mind.

Subsequently, when the Air Force and the Navy were enticed into joining the F-35 program — supposedly to benefit from the “savings” of a large 2,500 unit tri-service buy (savings that quickly turned into huge cost overruns) — they both had to accept the fat fuselage and lack of rearward visibility of the Marine Corps version.