DL 420 then AA 3972 at O'Hare
Savannah → Chicago → Bloomington-Normal
Timetable, Chicago time
13:13DL 420 from Savannah at the gate
12:59AA 3972 to Bloomington-Normal leaves the gate
23 h 46 apart on the timetable, overnight
AA 3972 leaves 23 h 46 after DL 420 arrives on the timetable: more than half a day, so not a connection we count.