AA 6468 then ET 3511 at O'Hare
St Louis → Chicago → Muscat
Timetable, Chicago time
15:03AA 6468 from St Louis at the gate
09:05ET 3511 to Muscat leaves the gate
18 h 02 apart on the timetable, overnight
ET 3511 leaves 18 h 02 after AA 6468 arrives on the timetable: more than half a day, so not a connection we count.