I can't really speak for the rest of the state but, in the late 50's / early 60's, Huntsville's Redstone Arsenal army base ended up as the home of NASA's Marsha

I can't really speak for the rest of the state but, in the late 50's / early 60's, Huntsville's Redstone Arsenal army base ended up as the home of NASA's Marshall Space Flight Center, as well as many of the post WW2 German rocket scientists. I think that over the decades, the focus on aerospace & defense has simply snowballed as more employers and workers are attracted to the area.