The blog post linked to by marlin was rather unimpressive IMO.
The writer of it ought to bear the following points in mind:
(a) The Indian radars covering the Andaman Islands may not have been on during the night because it was "too expensive" according to some reports recently.
(b) Also, there ought to be more coordination between different countries. You could have a situation where a plane hijacked by terrorists cleverly flies along the air borders between, for example, Malaysia, Thailand and Indonesia and none of those countries scrambles its fighter jets because they each think it's not in their territory, flying in the other direction, and "not a threat". The plane could then change direction at the last minute before an attack.