UA 5551 then AA 6281 at Denver
Idaho Falls → Denver → Los Angeles
Timetable, Denver time
19:20UA 5551 from Idaho Falls at the gate
18:46AA 6281 to Los Angeles leaves the gate
23 h 26 apart on the timetable, overnight
AA 6281 leaves 23 h 26 after UA 5551 arrives on the timetable: more than half a day, so not a connection we count.