AA 9866 then AA 312 at O'Hare
Marquette → Chicago → Dallas-Fort Worth
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
09:59AA 312 to Dallas-Fort Worth leaves the gate
23 h 29 apart on the timetable, overnight
AA 312 leaves 23 h 29 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.