F9 4567 then UA 2028 at Denver
St Louis → Denver → Ontario
Timetable, Denver time
21:30F9 4567 from St Louis at the gate
19:25UA 2028 to Ontario leaves the gate
21 h 55 apart on the timetable, overnight
UA 2028 leaves 21 h 55 after F9 4567 arrives on the timetable: more than half a day, so not a connection we count.