BA 1399 then AA 107 at Heathrow
Belfast City → London → New York JFK
Timetable, London time
16:25BA 1399 from Belfast City at the gate
15:35AA 107 to New York JFK leaves the gate
23 h 10 apart on the timetable, overnight
AA 107 leaves 23 h 10 after BA 1399 arrives on the timetable: more than half a day, so not a connection we count.