I just got the word from one of my son-in-laws:

Starting August 1, Coca-Cola Bottling Co. of Michigan (his employer) will begin delivering 30 pallets of assorted products weekly to NW/DL at Detroit Metro airport for catering the NW aircraft departing from there!!! Coke, Coke Zero, Sprite, and more are on the way!

I asked, but he did not know if this changeover was also going to take effect at MSP, MEM, and any other airports where NW planes might be catered. I won't make any assumptions, but maybe others have heard more news on this. As I am sipping my Coke by the lake today, enjoying my vacation, it is good to know that there are less than 30 days until I can begin sipping a Coke on my Northwest flight also!