It is the metal that you fly that matters and you flying on Emirates metal, you should be able to earn Emirates/Sri Lankan miles. For the US based airlines' FF programs, Emirates is listed as a partner for Delta/Continental & United, and so you should be able to ean the respective miles, but be aware of the fine print& the booking class. Also the Skyrewrads page at emirates.com lists BA/Singapore etc as earning partners, and so the reverse 'might' also be true, so check, depending on what program you want to earn miles.