I have several internal flights to book within Viet Nam and one from Ha Noi to Yangon for this coming October and November. We have never flown Viet Nam Airlines and know nothing about their pricing patterns, and thus how far to book ahead. Are their fare sales predictable. I have been told to book our Saigon to Phu Quoc ahead as those flights sell out quickly. Is business class worth the extra money? Is there anything unique to this airline that we should be aware? We will appreciate the advice. Thank you.