UA 3874 then UA 3513 at O'Hare
Chicago → Chicago → Providence
Timetable, Chicago time
01:21UA 3874 from Chicago at the gate
17:54UA 3513 to Providence leaves the gate
16 h 33 apart on the timetable
UA 3513 leaves 16 h 33 after UA 3874 arrives on the timetable: more than half a day, so not a connection we count.