AA 9866 then AA 1924 at O'Hare
Marquette → Chicago → Valparaiso
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
08:29AA 1924 to Valparaiso leaves the gate
21 h 59 apart on the timetable, overnight
AA 1924 leaves 21 h 59 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.