This is one of those little quirks of airfare I've never understood. My friend from HKG routes almost everything through BKK so he can buy his tickets in baht. I understand currencies fluctuate making it relatively cheaper to buy a ticket in one place versus another, but the consistently MUCH lower prices in Thailand versus the rest of the world make no sense.

Is this purely a marketing/differential-pricing thing for the airlines to sell tickets to (relatively) poor Thais who wouldn't be able to afford regular fares? Is there really that much less demand for airplane tickets in Thailand?