No, as of November 01 2006, the international airport departure tax will now be collected as JC tax on all tickets at the time of issue. It is already included in the price of your ticket.For your information - current rates of international airport tax in Vietnam are:

 

When departing at Ho Chi Minh City or Hanoi airport:
US$ 14.00 per person (adult)
US$ 7.00 per person (children aged 2-12 years old)
NO airport tax for infants under 2 years old
NO airport tax for passengers in transit between 2 international flights within 24 hours
When departing at Danang airport:
US$ 8.00 per person (adult)
US$ 4.00 per person (children aged 2-12 years old)
NO airport tax for infants under 2 years old
NO airport tax for passengers in transit between 2 international flights within 24 hours
Domestic air tickets are also included in the air tickets

 

Advised by: How to travel vietnam, Vietnam travel guide, vietnam travel advisor for for information