UA 503 then B6 1487 at Boston
Newark → Boston → Los Angeles
Timetable, Boston time
09:17UA 503 from Newark at the gate
09:05B6 1487 to Los Angeles leaves the gate
23 h 48 apart on the timetable, overnight
B6 1487 leaves 23 h 48 after UA 503 arrives on the timetable: more than half a day, so not a connection we count.