AA 9921 then ET 3511 at O'Hare
Phoenix → Chicago → Muscat
Timetable, Chicago time
16:00AA 9921 from Phoenix at the gate
09:05ET 3511 to Muscat leaves the gate
17 h 05 apart on the timetable, overnight
ET 3511 leaves 17 h 05 after AA 9921 arrives on the timetable: more than half a day, so not a connection we count.