WN 818 then DL 840 at Denver
Buffalo → Denver → Atlanta
Timetable, Denver time
18:35WN 818 from Buffalo at the gate
17:07DL 840 to Atlanta leaves the gate
22 h 32 apart on the timetable, overnight
DL 840 leaves 22 h 32 after WN 818 arrives on the timetable: more than half a day, so not a connection we count.