transit in Hanoi - live and direct!
Now that I'm in HAN I can answer this query.
Transit in HAN is pretty straight-forward. There is a tatty-looking transfer desk just before immigration, and when I arrived it was heaving with pax going on to Siem Reap and only one person checking them in. As my TG flight isn't for another few hours I didn't mind waiting.
I had gotten a Vietnam visa just in case as I wasn't sure of the transit arrangements. According to KA website you need to clear immigration and customs for transit but this obviously isn't the case. However I was informed that a visa is required if you are transitting in HAN on an international flight that makes an intermediate stop in SGN, since immigration will consider you to be 'in Vietnam' during that domestic sector.
To answer my own question, yes I could have taken the later KA flight but as there was a lot of unclear info out there, I thought I'd play it safe.
BTW the THAI/*A lounge is shared with most other carriers operating here. It's basic but functional with 11 PCs, photocopier, fax, smoking room and reasonable-looking food and drink. It sure beats waiting in the main departure area which looks really depressing. Staff are quite cheerful too.
HAN is pretty good for cheap TG biz fares so worth a look for anyone who can put up with the extra (minor) hassle.