AA 555 then UA 3914 at O'Hare
Houston → Chicago → Houston
Timetable, Chicago time
21:49AA 555 from Houston at the gate
20:30UA 3914 to Houston leaves the gate
22 h 41 apart on the timetable, overnight
UA 3914 leaves 22 h 41 after AA 555 arrives on the timetable: more than half a day, so not a connection we count.