AA 1260 then CA 3174 at O'Hare
Boston → Chicago → Guangzhou
Timetable, Chicago time
18:55AA 1260 from Boston at the gate
13:40CA 3174 to Guangzhou leaves the gate
18 h 45 apart on the timetable, overnight
CA 3174 leaves 18 h 45 after AA 1260 arrives on the timetable: more than half a day, so not a connection we count.