UA 1591 then DL 1421 at San Francisco
San Antonio → San Francisco → Los Angeles
Timetable, San Francisco time
11:02UA 1591 from San Antonio at the gatealso NZ 2372, UA 2490, AC 4201, EK 6003
09:54DL 1421 to Los Angeles leaves the gatealso KL 6896, LA 8934, LA 8950
22 h 52 apart on the timetable, overnight
DL 1421 leaves 22 h 52 after UA 1591 arrives on the timetable: more than half a day, so not a connection we count.