AA 9866 then UA 5477 at O'Hare
Marquette → Chicago → Oklahoma City
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
08:50UA 5477 to Oklahoma City leaves the gate
22 h 20 apart on the timetable, overnight
UA 5477 leaves 22 h 20 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.