It seems like Asian and Middle east carriers show reg on wings but US carriers do not?

I don't think European airlines show the registration on the wings as well. I think only a handful of South American Airlines have the registration on the wing (I.e. Avianca on some aircrafts).

Hi, I think you will find that most of the worlds airline DO show the regs under the wing/wings its only the german and american planes that dont, why I dont know. Hope this helps. Regards. Roger