UA 3874 then AA 3205 at O'Hare
Chicago → Chicago → Phoenix
Timetable, Chicago time
01:21UA 3874 from Chicago at the gate
20:50AA 3205 to Phoenix leaves the gate
19 h 29 apart on the timetable
AA 3205 leaves 19 h 29 after UA 3874 arrives on the timetable: more than half a day, so not a connection we count.