UA 602 then CA 3174 at O'Hare
Miami → Chicago → Guangzhou
Timetable, Chicago time
19:04UA 602 from Miami at the gate
13:40CA 3174 to Guangzhou leaves the gate
18 h 36 apart on the timetable, overnight
CA 3174 leaves 18 h 36 after UA 602 arrives on the timetable: more than half a day, so not a connection we count.