AA 1260 then K4 221 at O'Hare
Boston → Chicago → Cincinnati Northern Kentucky
Timetable, Chicago time
18:55AA 1260 from Boston at the gate
16:20K4 221 to Cincinnati Northern Kentucky leaves the gate
21 h 25 apart on the timetable, overnight
K4 221 leaves 21 h 25 after AA 1260 arrives on the timetable: more than half a day, so not a connection we count.