AA 5003 then UA 5201 at O'Hare
Detroit → Chicago → Milwaukee
Timetable, Chicago time
07:30AA 5003 from Detroit at the gate
20:00UA 5201 to Milwaukee leaves the gate
12 h 30 apart on the timetable
UA 5201 leaves 12 h 30 after AA 5003 arrives on the timetable: more than half a day, so not a connection we count.