UA 3912 then AA 1841 at Phoenix
Denver → Phoenix → Ontario
Timetable, Phoenix time
23:32UA 3912 from Denver at the gate
21:51AA 1841 to Ontario leaves the gate
22 h 19 apart on the timetable, overnight
AA 1841 leaves 22 h 19 after UA 3912 arrives on the timetable: more than half a day, so not a connection we count.