Probably the way this inarticulate bozo stated it.
However, in getting an MBA, I learned that Boeing messed up big time by not shifting, say some of the wing
construction to the only European firm that could do it, essentially eliminating a necessary and strategic
component from a startup called Airbus. Politics probably would have doomed purchases from the then Soviet Union.
Likewise, Catepillar tries to shift production around the world to try to balance where they will benefit from
world economic situation at any given instant. Not to mention a strike in one area will not shut down
production.
My understanding of this issue is that building the wing is the true "black art" of airplane construction. They wish to keep production that component in the US to ensure that no one else takes their engineering and applies it to their products.
Regarding oversees production, I believe that many countries have domestic content rules for certain purchases. Airplanes fall into this category, so in order to be able to sell them the planes they set up shop in those countries to produce enough of the content there to satisfy the requirements.
It makes for difficult decisions - either don't make the sales in those countries or produce some of the content there and make the sale. I believe that a large portion of the tailsections for Boeing's planes are made in China as a result of the large purchase the Chinese made a few years back.
Their main competitor - Airbus - is heavily subsidized and it is difficult to compete in a market where your competitor is playing by a different set of rules.