AA 986 then UA 5539 at O'Hare
Baltimore → Chicago → Moline
Timetable, Chicago time
08:50AA 986 from Baltimore at the gate
21:47UA 5539 to Moline leaves the gate
12 h 57 apart on the timetable
UA 5539 leaves 12 h 57 after AA 986 arrives on the timetable: more than half a day, so not a connection we count.