Southeast Asia forum

Hi,

First off, when my girlfriend and I last travelled for 4 1/2 months in Vietnam, Laos, Thailand and Singapore, the two key budget airlines we used were Air Asia and Jetstar, and neither of these can be found on most search engine sites... I'd recommend going straight to their websites and booking there.  

To answer your question, I wouldn't book many (if any) domestic/regional SE Asia flights before you leave - we didn't.  However, don't wait until a few days before you want to fly and expect to get a cheap flight.  What we did was basically decide where we wanted to be about two or three weeks in advance, and were usually (but not always) able to find a cheap flight on either Air Asia or Jetstar.  

If we decided to go somewhere more spontaneously - or if flights were too expensive - we just took busses/trains, which given the amount of time you have is not the end of the world.  But it is nice to fly some legs...  We did Singapore to HCMC on Jetstar, Da Nang to Ha Noi on Jetstar (and back), Bangkok to HCMC on Air Asia, and then HCMC to Singapore on Jetstar again, and all of these we booked for cheap at least 10 days in advance.  In regard to major legs towards the end of our trip like BKK to HCMC, there were times when we just had to prioritize, make a decision a few weeks in advance and stick to it.  However the majority of our longer legs were done by bus or train, and we never had much of a problem with that, although the haul from Hoi An to Vientiane by bus was a little grueling.

Luckily for you, you've got a good amount of time, so I wouldn't stress the details too much...  On our trip we did start with a basic plan but ended up completely changing it as we went, and that ability to be spontaneous was really nice.

Have fun, 

DL