AA 9866 then UA 4382 at O'Hare
Bloomington-Normal → Chicago → Buffalo
Timetable, Chicago time
13:11AA 9866 from Bloomington-Normal at the gate
10:30UA 4382 to Buffalo leaves the gate
21 h 19 apart on the timetable, overnight
UA 4382 leaves 21 h 19 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.