AA 9909 then UA 1281 at Denver
Los Angeles → Denver → San Diego
Timetable, Denver time
16:45AA 9909 from Los Angeles at the gate
15:45UA 1281 to San Diego leaves the gate
23 h apart on the timetable, overnight
UA 1281 leaves 23 h after AA 9909 arrives on the timetable: more than half a day, so not a connection we count.