F9 4409 then DL 2780 at Atlanta
Washington → Atlanta → Dallas
Timetable, Atlanta time
23:13F9 4409 from Washington at the gate
16:46DL 2780 to Dallas leaves the gate
17 h 33 apart on the timetable, overnight
DL 2780 leaves 17 h 33 after F9 4409 arrives on the timetable: more than half a day, so not a connection we count.