AA 2556 then K4 221 at O'Hare
San Diego → Chicago → Cincinnati Northern Kentucky
Timetable, Chicago time
19:59AA 2556 from San Diego at the gate
16:20K4 221 to Cincinnati Northern Kentucky leaves the gate
20 h 21 apart on the timetable, overnight
K4 221 leaves 20 h 21 after AA 2556 arrives on the timetable: more than half a day, so not a connection we count.