AA 6255 then ET 3511 at O'Hare
Sioux Falls → Chicago → Muscat
Timetable, Chicago time
17:30AA 6255 from Sioux Falls at the gate
09:05ET 3511 to Muscat leaves the gate
15 h 35 apart on the timetable, overnight
ET 3511 leaves 15 h 35 after AA 6255 arrives on the timetable: more than half a day, so not a connection we count.