AA 581 then UA 535 at O'Hare
Miami → Chicago → Houston
Timetable, Chicago time
09:30AA 581 from Miami at the gate
09:21UA 535 to Houston leaves the gate
23 h 51 apart on the timetable, overnight
UA 535 leaves 23 h 51 after AA 581 arrives on the timetable: more than half a day, so not a connection we count.