UA 1256 then WN 1749 at Denver
Knoxville → Denver → Dallas
Timetable, Denver time
10:28UA 1256 from Knoxville at the gate
06:05WN 1749 to Dallas leaves the gate
19 h 37 apart on the timetable, overnight
WN 1749 leaves 19 h 37 after UA 1256 arrives on the timetable: more than half a day, so not a connection we count.