UA 4480 then AA 3974 at O'Hare
Fargo → Chicago → Harrisburg
Timetable, Chicago time
09:30UA 4480 from Fargo at the gate
08:27AA 3974 to Harrisburg leaves the gate
22 h 57 apart on the timetable, overnight
AA 3974 leaves 22 h 57 after UA 4480 arrives on the timetable: more than half a day, so not a connection we count.