UA 747 then CA 3174 at O'Hare
Seattle (SEA) → Chicago → Guangzhou
Timetable, Chicago time
17:00UA 747 from Seattle (SEA) at the gate
13:40CA 3174 to Guangzhou leaves the gate
20 h 40 apart on the timetable, overnight
CA 3174 leaves 20 h 40 after UA 747 arrives on the timetable: more than half a day, so not a connection we count.