WN 209 then WN 1639 at Denver
St Louis → Denver → Las Vegas
Timetable, Denver time
18:50WN 209 from St Louis at the gate
17:25WN 1639 to Las Vegas leaves the gate
22 h 35 apart on the timetable, overnight
WN 1639 leaves 22 h 35 after WN 209 arrives on the timetable: more than half a day, so not a connection we count.