I moved 202,000 MR points this past Wednesday. The AmEx phone operator had no problem doing it. They're already in my online TWA balance.
If your Aviators account is already registered with MR, you can transfer on the Web at
http://www.americanexpress.com/rewards. Otherwise, you have to call AmEx to register that account with them before you can transfer into it. You can transfer the points in the same call. The numbers are 800-AXP-EARN (800-297-3276); from overseas 305-816-2799 collect. (This URL and these numbers are all public.)