AA 3547 then CZ 2508 at O'Hare
St Louis → Chicago → Guangzhou
Timetable, Chicago time
21:51AA 3547 from St Louis at the gate
19:50CZ 2508 to Guangzhou leaves the gate
21 h 59 apart on the timetable, overnight
CZ 2508 leaves 21 h 59 after AA 3547 arrives on the timetable: more than half a day, so not a connection we count.