DL 5740 then AA 4743 at Boston
Philadelphia → Boston → Buffalo
Timetable, Boston time
07:26DL 5740 from Philadelphia at the gate
19:50AA 4743 to Buffalo leaves the gate
12 h 24 apart on the timetable
AA 4743 leaves 12 h 24 after DL 5740 arrives on the timetable: more than half a day, so not a connection we count.