American Airlines, JAL, and Cathay Pacific, have round-trip flights from Dallas (DFW) to Bangkok (BKK) for $726-$739 with a connection. Flights October, November, January, February, and March. No Weekends. Departures on Monday, Tuesday, Wednesday, and Thursday. Extended Weekends available.
Note: Carry-on bag is allowed for free on American Airlines, JAL, and Cathay Pacific. You can avoid paying for seat selection by accepting the randomly assigned seat at the gate.
Note: Avoid similarly priced flights on Qatar, those have long connection times and inferior routing.