AA 9866 then UA 535 at O'Hare
Marquette → Chicago → Houston
Timetable, Chicago time
10:30AA 9866 from Marquette at the gate
09:21UA 535 to Houston leaves the gate
22 h 51 apart on the timetable, overnight
UA 535 leaves 22 h 51 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.