AA 4455 then UA 360 at Boston
Washington National → Boston → Los Angeles
Timetable, Boston time
08:26AA 4455 from Washington National at the gate
08:25UA 360 to Los Angeles leaves the gate
23 h 59 apart on the timetable, overnight
UA 360 leaves 23 h 59 after AA 4455 arrives on the timetable: more than half a day, so not a connection we count.