Exactly: Spinning off Spirit makes no sense in terms of outsourcing: It was Boeing's own factory that formed the basis of Spirit, which made Spirit a sole-supplier of critical components with exactly zero technical advantage, and exactly zero capacity advantage over doing it in house.

So why do it? It makes return on net assets look better? It makes unions fragmented and weaker? It provides a third party to blame when they shortchange quality? It takes soon-to-be obsolete production capital off the books? But nothing that actually makes anything about making planes better.