UA 1256 then WN 581 at Denver
Knoxville → Denver → Nashville
Timetable, Denver time
10:28UA 1256 from Knoxville at the gate
07:55WN 581 to Nashville leaves the gate
21 h 27 apart on the timetable, overnight
WN 581 leaves 21 h 27 after UA 1256 arrives on the timetable: more than half a day, so not a connection we count.