F9 1449 then WN 1749 at Denver
Atlanta → Denver → Dallas
Timetable, Denver time
08:22F9 1449 from Atlanta at the gate
06:05WN 1749 to Dallas leaves the gate
21 h 43 apart on the timetable, overnight
WN 1749 leaves 21 h 43 after F9 1449 arrives on the timetable: more than half a day, so not a connection we count.