UA 3874 then AA 4663 at O'Hare
Chicago → Chicago → Memphis
Timetable, Chicago time
01:21UA 3874 from Chicago at the gate
16:00AA 4663 to Memphis leaves the gate
14 h 39 apart on the timetable
AA 4663 leaves 14 h 39 after UA 3874 arrives on the timetable: more than half a day, so not a connection we count.