AA 9866 then AA 3697 at O'Hare
Marquette → Chicago → Missoula
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
09:40AA 3697 to Missoula leaves the gate
23 h 10 apart on the timetable, overnight
AA 3697 leaves 23 h 10 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.