AA 4264 then UA 3874 at O'Hare
Sioux Falls → Chicago → LCQ
Timetable, Chicago time
09:02AA 4264 from Sioux Falls at the gate
06:30UA 3874 to LCQ leaves the gate
21 h 28 apart on the timetable, overnight
UA 3874 leaves 21 h 28 after AA 4264 arrives on the timetable: more than half a day, so not a connection we count.