UA 4686 then WN 988 at Denver
Little Rock → Denver → Buffalo
Timetable, Denver time
15:11UA 4686 from Little Rock at the gate
11:50WN 988 to Buffalo leaves the gate
20 h 39 apart on the timetable, overnight
WN 988 leaves 20 h 39 after UA 4686 arrives on the timetable: more than half a day, so not a connection we count.