DL 2503 then CA 3174 at O'Hare
New York LaGuardia → Chicago → Guangzhou
Timetable, Chicago time
19:25DL 2503 from New York LaGuardia at the gate
13:40CA 3174 to Guangzhou leaves the gate
18 h 15 apart on the timetable, overnight
CA 3174 leaves 18 h 15 after DL 2503 arrives on the timetable: more than half a day, so not a connection we count.