For those that have never used it, the Discovery Airpass is a really convenient and reasonably priced option for regional travel. There are some restrictions: Travelers need to buy at least 3 legs and book the tickets prior to arriving in Asia and can only fly into each city once unless in transit to another destination. Routing includes domestic and international flights on Bangkok Airways and Lao Airlines. It is possible to reach every airport in Thailand, Lao and Cambodia plus depending on your routing, international destinations like Hong Kong, Singapore, Mumbai, Saigon, Hanoi, Malé (Maldives), Yangon (RGN) and Kaula Lampur. A typical itenarary of 3 international flgihts (for example: Bangkok to Siem Reap to Luang Prabang and back to Bangkok) will run you in the neighborhood of $525 including taxes. An all domestic schedule will be considerably less.
We’ve used Discovery AirPass tickets on our last 3 of our last 4 trips to Southeast Asia and have had no problems with check-in at the airport, (no) charges for overweight baggage or flights running late. In fact, we have discovered that particularly with Lao Airlines that more often than not, flights depart anywhere from 15-30 minutes ahead of schedule.
Typically Bangkok Air uses the Airbus 319 for most flights and Lao Airways uses ATR 72 or ATR 42 turboprops. Service on both has consistently been good and flights about as smooth as could be expected in the tropics.
There are limited seats on each flight allocated to Airpass rates so you should book as far in advance as possible to insure getting the best selection of flights.