<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by keithguy:
There's also a Finnair BKK-SIN flight that operates Mon, Wed, Fri, Sun. So you could go JFK-AA-NRT-AA-BKK-AY-SIN.
The AY flights leave at 3:30pm.</font>
Yup. There's arguably a bit of a downside -- less notable lounges at BKK, and a greater distance between city and airport, requiring more travel time and reducing the value of the stopover. But definitely a possibility.
And same for any of the other AA codeshare destinations beyond NRT.