DL 939 then DL 1 at JFK
Los Angeles → New York → London Heathrow
Timetable, New York time
20:59DL 939 from Los Angeles at the gate
20:00DL 1 to London Heathrow leaves the gate
23 h 01 apart on the timetable, overnight
DL 1 leaves 23 h 01 after DL 939 arrives on the timetable: more than half a day, so not a connection we count.