> Only if the plane is partly a passenger plane. If it would be a pure cargo plane, the whole back could be unpressurized, or am I missing something? I'd guess

> Only if the plane is partly a passenger plane. If it would be a pure cargo plane, the whole back could be unpressurized, or am I missing something? I'd guess you'd get stress issues in the bulkhead behind the cockpit if you tried that. You'd need to completely redesign the joint between the cockpit section of the fuselage and everything behind it. And then, for your trouble, you've given up the ability to transport anything that can't tolerate the pressure and temperature swings of an unpressurized cabin. Given that the pressurization systems are already implemented and don't seem to hurt efficiency much (afaik they typically run off engine bleed air), I don't think there's much reason not to just pressurize the whole thing. I guess it probably makes the structure marginally heavier, but at that point you may as well just design a whole new airplane.