AA 9866 then AA 249 at O'Hare
Marquette → Chicago → Mexico City
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
08:45AA 249 to Mexico City leaves the gate
22 h 15 apart on the timetable, overnight
AA 249 leaves 22 h 15 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.