AA 111 then UA 3910 at O'Hare
Rome → Chicago → Chicago
Timetable, Chicago time
14:10AA 111 from Rome at the gate
05:30UA 3910 to Chicago leaves the gate
15 h 20 apart on the timetable, overnight
UA 3910 leaves 15 h 20 after AA 111 arrives on the timetable: more than half a day, so not a connection we count.