UA 3874 then AA 6339 at O'Hare
Chicago Rockford → Chicago → Kansas City
Timetable, Chicago time
01:21UA 3874 from Chicago Rockford at the gate
15:42AA 6339 to Kansas City leaves the gate
14 h 21 apart on the timetable
AA 6339 leaves 14 h 21 after UA 3874 arrives on the timetable: more than half a day, so not a connection we count.