As for the south...many people are incredibly ignorant and uneducated there. It's truly astounding. My mother is from Mississippi and I've been down there plenty. Not to say there aren't plenty of smart people, and even the uneducated ones (over 80% of the population, easily) aren't outright stupid. However, I can guarantee that on the whole the quality of labor in the south is absolutely lower than in the northern states I've been to. I haven't been to Seattle, but I imagine it's similar. While I'm sure Boeing would hire competent people and maintain quality, I don't think the fear of diminished quality is at all unfounded.
Like I said before, I worked as a project manager for a mechanical contractor. I have worked everywhere from Green Bay to Memphis to Indianapolis, to Cincinnati to Dallas, TX and I can say without a doubt there are smart, hardworking people everywhere you go in the United States. There are also uneducated people anywhere you go.
Just because people talk slower doesn't make them dumb.
Skilled trade unions aren't anything special. I agree that they are a good way to get on the job training while working in your chosen field of interest. However, they are not the only way for a skilled worker to get proper training in any given field.
I have also known a lot of skilled trade union members that go outside the union because they are hard working and can move up faster and get paid above scale rather than get the regimented raises like their union counterparts.
If the workforce in the South was that bad, I'm sure Honda and Toyota wouldn't have built assembly plants down there.
Finally, I know we are talking about Boeing, but we aren't talking about hiring 5,000 mechanical engineers. I'm sure there are one or two assembly line jobs at this new plant.