AA 9866 then UA 543 at O'Hare
Bloomington-Normal → Chicago → San Francisco
Timetable, Chicago time
13:11AA 9866 from Bloomington-Normal at the gate
10:25UA 543 to San Francisco leaves the gate
21 h 14 apart on the timetable, overnight
UA 543 leaves 21 h 14 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.