UA 3874 then AA 3542 at O'Hare
Chicago Rockford → Chicago → Columbus (Ohio)
Timetable, Chicago time
01:21UA 3874 from Chicago Rockford at the gate
15:28AA 3542 to Columbus (Ohio) leaves the gate
14 h 07 apart on the timetable
AA 3542 leaves 14 h 07 after UA 3874 arrives on the timetable: more than half a day, so not a connection we count.