SQ 1543 then B6 978 at San Francisco
New York JFK → San Francisco → Fort Lauderdale
Timetable, San Francisco time
13:40SQ 1543 from New York JFK at the gate
13:20B6 978 to Fort Lauderdale leaves the gate
23 h 40 apart on the timetable, overnight
B6 978 leaves 23 h 40 after SQ 1543 arrives on the timetable: more than half a day, so not a connection we count.