DL 3968 then DL 281 at Seattle
Vancouver → Seattle → Shanghai
Timetable, Seattle time
16:53DL 3968 from Vancouver at the gate
14:40DL 281 to Shanghai leaves the gate
21 h 47 apart on the timetable, overnight
DL 281 leaves 21 h 47 after DL 3968 arrives on the timetable: more than half a day, so not a connection we count.