Earning on codeshare
 

I noticed a SQ metal flight with an AI # and an M booking class, would this elibible for M+ ? or does a flight have to operated and marketed by SQ?

Most likely. I had a LH flight from Frankfurt to Doha, Qatar. Turned out to be a Qatar Airways codeshare flight; no miles for me. :(

That's strange as Qatar and LH are partners, so somebody could have given you the miles. Anyways my situation involves one non-member. AA seems quite definitive about its codeshares in that its codeshares on other flights operate under its rules, just wish UA could staighten that aspect.