AA 1253 then CA 3174 at O'Hare
San Francisco → Chicago → Guangzhou
Timetable, Chicago time
17:05AA 1253 from San Francisco at the gate
13:40CA 3174 to Guangzhou leaves the gate
20 h 35 apart on the timetable, overnight
CA 3174 leaves 20 h 35 after AA 1253 arrives on the timetable: more than half a day, so not a connection we count.