DL 957 then WN 988 at Denver
Atlanta → Denver → Buffalo
Timetable, Denver time
13:15DL 957 from Atlanta at the gate
11:50WN 988 to Buffalo leaves the gate
22 h 35 apart on the timetable, overnight
WN 988 leaves 22 h 35 after DL 957 arrives on the timetable: more than half a day, so not a connection we count.