AA 4788 then DL 2804 at Boston
Buffalo → Boston → Chicago O'Hare
Timetable, Boston time
08:36AA 4788 from Buffalo at the gate
20:40DL 2804 to Chicago O'Hare leaves the gate
12 h 04 apart on the timetable
DL 2804 leaves 12 h 04 after AA 4788 arrives on the timetable: more than half a day, so not a connection we count.