Boeing is the final assembler of major commercial aircraft, but a Boeing doesn’t go anywhere without GE or United Technologies powerplants, for instance. Boeing Commercial has about 8,000 suppliers in the U.S., and does something like $13 billion in business with them.
Commercial aerospace never embraced vertical integration the way the Detroit empire-builders attempted. That may be one reason why they remained cutting-edge.
Japan does indeed build military aircraft—google the J-2, for instance, and is a major Boeing partner on the 787. Japanese heavy industry does not launch a competing finished commercial aircraft product because they have been nearly completely incorporated into the Boeing supply chain.
China, on the other hand, is quite likely to launch a small (c. 100 seat) commercial aircraft for domestic consumption and international prestige purposes in the very near future.
But to circle around to your larger question, I would nominate heavy engine and construction manufacturers like Caterpillar, Case, Navistar and Cummins as standard-bearers in industrial manufacture.
I don’t think they’re “state of the art” in the same sense as Boeing, but they’re all clearly world-class.
And, of course, petroleum engineering is another industrial sector in which the U.S. apologises to no one.
Industry does not revolve around Detroit, no matter what the people of Michigan may have come to believe. If the last manufacturer headquartered in Detroit turns out its lights, life will indeed go on just the way it did when Studebaker shut down in Indiana.
They already have with the ACAC ARJ21, which is derived from the McDonnell-Douglas MD90 design. The first prototype recently started test flying and first deliveries should start some time in the fourth quarter of 2009.
Here a picture of the prototype: