GateConnections

AA 9866 then AA 2389 at O'Hare

Marquette → Chicago → Calgary

Timetable, Chicago time

10:30AA 9866 from Marquette at the gate

10:00AA 2389 to Calgary leaves the gate

23 h 30 apart on the timetable, overnight

AA 2389 leaves 23 h 30 after AA 9866 arrives on the timetable: more than half a day, so not a connection we count.