Originally Posted by
jiejie
May is the secret, not the Krabi routing. The DA is much more viable if traveling in a relatively low season such as May through October, due to emptier planes and opening of L class availability. Bangkok Airways knows that they can fill up their planes December through February even at the higher ticket price points and of course that makes more business sense than letting loose a bunch of discounted seats via the Airpass.
May is definitely the reason it worked.
I'd hesitate to refer to the reason as the 'opening of L class' however. With the exception of BKK-USM where L is rarely available most, if not all, other segments regularly have Q and H, lower fare classes, also available. The trick is to grab the L fares before they get bought by o/w and simple r/t purchases.
The big trick to working DA effectively is use it for o/w international legs and limit the domestic legs to only those needed to reach the 3 segment minimum. If you can avoid domestic segments you'll get better value out of the ticket.