VU 305 then VZ 204 at Bangkok
Hanoi → Bangkok → Udon Thani
Timetable, Bangkok time
14:10VU 305 from Hanoi at the gate
13:15VZ 204 to Udon Thani leaves the gate
23 h 05 apart on the timetable, overnight
VZ 204 leaves 23 h 05 after VU 305 arrives on the timetable: more than half a day, so not a connection we count.