AA 1968 then CZ 2508 at O'Hare
Tucson → Chicago → Guangzhou
Timetable, Chicago time
20:20AA 1968 from Tucson at the gate
19:50CZ 2508 to Guangzhou leaves the gate
23 h 30 apart on the timetable, overnight
CZ 2508 leaves 23 h 30 after AA 1968 arrives on the timetable: more than half a day, so not a connection we count.