SQ 1543 then OZ 9521 at San Francisco
New York JFK → San Francisco → Houston
Timetable, San Francisco time
19:31SQ 1543 from New York JFK at the gate
16:40OZ 9521 to Houston leaves the gate
21 h 09 apart on the timetable, overnight
OZ 9521 leaves 21 h 09 after SQ 1543 arrives on the timetable: more than half a day, so not a connection we count.