Originally Posted by
moondog
Since that breaks the "single partner" rule, and DFW-SIN is a LONG flight (2+ partner awards are distance based, as you know from your own research), I'm afraid that Happy's advice is spot on. However, since AA flies DFW-NRT nonstop, I'd be tempted to grab that and use UA miles for NRT-SIN (currently 30k miles RT in C or 20k in Y).
ETA: It might be possible to score a JL flight number on DFW-NRT. I know code shares aren't supposed to work, but since PDX-LAX does, this would be worthy of further investigation.
Thanks for the response! And thanks for pointing out another alternative of using my BA miles from DFW to NRT and using my AA miles (I currently have 40K AA miles) from NRT to SIN. ^^ However, when I tried booking a ticket from DFW to NRT thru BA website, it showed that I was short around 40K miles. I currently have 50K miles in the BA account. So, I need
90K to fly from DFW to NRT on an economy class. I was surprised it takes 90K miles to fly DFW-NRT using BA miles on AA while I only need 70K to fly DFW-NRT-SIN using AA miles on AA and JAL.