WN 855 then WN 4326 at Denver
Dallas → Denver → Tulsa
Timetable, Denver time
07:10WN 855 from Dallas at the gate
15:15WN 4326 to Tulsa leaves the gate
8 h 05 apart on the timetable
The last days
WN 855 and WN 4326 weren’t both flown 15 min to 12 h apart in the last 21 days.
Statistics from past flights, not live flight information. Always check times and your connection with your airline, and don’t base travel or booking decisions on these numbers.