AA 642 then UA 4504 at O'Hare
Dallas-Fort Worth → Chicago → Sioux Falls
Timetable, Chicago time
13:10AA 642 from Dallas-Fort Worth at the gate
08:40UA 4504 to Sioux Falls leaves the gate
19 h 30 apart on the timetable, overnight
UA 4504 leaves 19 h 30 after AA 642 arrives on the timetable: more than half a day, so not a connection we count.