UA 1783 then AA 4444 at Boston
Los Angeles → Boston → New York JFK
Timetable, Boston time
17:38UA 1783 from Los Angeles at the gate
17:30AA 4444 to New York JFK leaves the gate
23 h 52 apart on the timetable, overnight
AA 4444 leaves 23 h 52 after UA 1783 arrives on the timetable: more than half a day, so not a connection we count.