GREAT price for roundtrip flights from New York City (JFK) to Bangkok on Asiana Airlines! Asiana is an awesome airline. Once you get to Bangkok, it's very cheap to travel around Southeast Asia!
DATES: Available November - mid December, and mid-January through April (some black out dates around Spring Break mid-April). Earliest departure date we found was October 30, and latest departure date is May 1.
BOOKING: Search on Google Flights for dates and cheapest booking options. Cheapest booking site for our sample dates of Jan 16 - 27 was through Orbitz (screenshot below). Booking direct on Asiana was about $20 more.
There are similar fares on China Eastern and other Chinese Airlines. I narrowed search option to just show Asiana flights.
*NOTE - return flight only allows 1.5 hour layover in Incheon Airport in South Korea. This should be enough time to make connecting flight if no delays. Airport is very efficient and minimum layover for international flights is 45 minutes. But, be well aware of the short layover.