AA 4504 then UA 5201 at O'Hare
Dayton → Chicago → Milwaukee
Timetable, Chicago time
07:23AA 4504 from Dayton at the gate
20:00UA 5201 to Milwaukee leaves the gate
12 h 37 apart on the timetable
UA 5201 leaves 12 h 37 after AA 4504 arrives on the timetable: more than half a day, so not a connection we count.