UA 3501 then AA 2663 at O'Hare
Detroit → Chicago → Harrisburg
Timetable, Chicago time
06:57UA 3501 from Detroit at the gate
19:20AA 2663 to Harrisburg leaves the gate
12 h 23 apart on the timetable
AA 2663 leaves 12 h 23 after UA 3501 arrives on the timetable: more than half a day, so not a connection we count.