AA 3974 then UA 6080 at O'Hare
Harrisburg → Chicago → Saginaw
Timetable, Chicago time
13:30AA 3974 from Harrisburg at the gate
13:25UA 6080 to Saginaw leaves the gate
23 h 55 apart on the timetable, overnight
UA 6080 leaves 23 h 55 after AA 3974 arrives on the timetable: more than half a day, so not a connection we count.