AA 2166 then UA 3910 at O'Hare
Boston → Chicago → Newark
Timetable, Chicago time
12:29AA 2166 from Boston at the gate
07:30UA 3910 to Newark leaves the gate
19 h 01 apart on the timetable, overnight
UA 3910 leaves 19 h 01 after AA 2166 arrives on the timetable: more than half a day, so not a connection we count.