http://www.packagemapping.com/ is showing that my phone (which departed Zhengzhou at 5:30 pm local time) went straight to Louisville, KY and will be landing soon. Not sure how accurate that website is.
Did your phone, by any chance, for some reason re-check in @ Zhengzhou @ 6PM local?
My 5s has made a stop in Korea according to UPS tracking. Apparently not on that China-Alaska flight mentioned above.