Originally Posted by mshaikun
But can you transfer from AA to Diners Club in new MC system? It is easy to get miles into an airline program, but all but impossible to get them out other than through use.
WIth most other programs, yes.
But AA is the big exception. It has all sorts of choices for converting OUT of AA into other programs (including still DC-MC) or other awards (than airline flights). Look:
https://redeemaamiles.points.com/home.jsp