More familiar with Little Saigon in Fort Worth, but I'm sure there is an equivalent in Big D.

I would suggest using a Vietnamese TA as they may have access to consolidator fares that will beat the pants off anything you can find. Or not.

Long time ago I used a Taiwanese TA in Houston to book an EVA flight (Taiwanese carrier) and to this day I'm convinced that I got better seats in Economy Plus (which is MUCH cheaper than Biz). Flew on CO (now UA) to from LAX on same ticket, but NONE of US carriers have PE