AA 9909 then UA 5651 at Denver
Los Angeles → Denver → Tucson
Timetable, Denver time
16:45AA 9909 from Los Angeles at the gate
16:05UA 5651 to Tucson leaves the gate
23 h 20 apart on the timetable, overnight
UA 5651 leaves 23 h 20 after AA 9909 arrives on the timetable: more than half a day, so not a connection we count.