AA 2537 then K4 221 at O'Hare
Tucson → Chicago → Cincinnati Northern Kentucky
Timetable, Chicago time
20:15AA 2537 from Tucson at the gate
16:20K4 221 to Cincinnati Northern Kentucky leaves the gate
20 h 05 apart on the timetable, overnight
K4 221 leaves 20 h 05 after AA 2537 arrives on the timetable: more than half a day, so not a connection we count.