UA 568 then AA 2951 at DFW
Denver → Dallas-Fort Worth → Las Vegas
Timetable, Dallas-Fort Worth time
12:44UA 568 from Denver at the gate
12:15AA 2951 to Las Vegas leaves the gate
23 h 31 apart on the timetable, overnight
AA 2951 leaves 23 h 31 after UA 568 arrives on the timetable: more than half a day, so not a connection we count.