You might want to read this.

http://www.smarttravelasia.com/smallairlines.htm

Additionally, I would do a Google Search for "discount airlines asia" which should yield you a web page listing airlines by country of ownership. I believe Tiger Air flies from SIN to SGN.

I am flying next week BKK-SGN on AF for $181 U.S. RT booked on the phone in the U.S. It was $211 on the Air France Thailand web-site. You have to fax credit card to them to book. U.S. booking is simple with credit card taken over the phone.

You might also try www.tnktravelvietnam.com or e-mail [email protected] asking her (Miss Nhu) to research the cheapest ticket. She is handling my internal Vietnam ticketing.

Remember that sometimes it is cheaper to buy a RT and get diverted on the return.