DL 420 then AA 3890 at O'Hare
Savannah → Chicago → Sioux Falls
Timetable, Chicago time
13:13DL 420 from Savannah at the gate
12:26AA 3890 to Sioux Falls leaves the gate
23 h 13 apart on the timetable, overnight
AA 3890 leaves 23 h 13 after DL 420 arrives on the timetable: more than half a day, so not a connection we count.