They design here, but that's still a very limited presence. If you look at accompanying industries with large capital investment - like semi-conductors (Texas Instruments) - typically less than 10% of the workforce is devoted to the design phase. For every prototype engineer there's 10 mechanical/electrical engineers and a 100 techs in the background. My grandfather and uncle both worked in development for Saturn, so this is slight hearsay, but my remarks about T.I. are firsthand.
Most of the basic parts are produced overseas. We still produce electronics and assemble the parts. I realize since the recession some of the more menial construction has actually returned, but I don't think it will ever resemble the 1940s/1950s. Germany and Japan were both out of the picture and Korea didn't even exist on anyone's radar.