UA 3917 then AV 2157 at San Francisco
Los Angeles → San Francisco → Los Angeles
Timetable, San Francisco time
19:00UA 3917 from Los Angeles at the gate
18:55AV 2157 to Los Angeles leaves the gate
23 h 55 apart on the timetable, overnight
AV 2157 leaves 23 h 55 after UA 3917 arrives on the timetable: more than half a day, so not a connection we count.