AA 4479 then UA 4645 at O'Hare
Pittsburgh → Chicago → Fort Wayne
Timetable, Chicago time
14:00AA 4479 from Pittsburgh at the gate
11:25UA 4645 to Fort Wayne leaves the gate
21 h 25 apart on the timetable, overnight
UA 4645 leaves 21 h 25 after AA 4479 arrives on the timetable: more than half a day, so not a connection we count.