AA 3974 then ET 3511 at O'Hare
Harrisburg → Chicago → Muscat
Timetable, Chicago time
15:34AA 3974 from Harrisburg at the gate
09:05ET 3511 to Muscat leaves the gate
17 h 31 apart on the timetable, overnight
ET 3511 leaves 17 h 31 after AA 3974 arrives on the timetable: more than half a day, so not a connection we count.