WN 645 then UA 4500 at Detroit
St Louis → Detroit → Washington
Timetable, Detroit time
12:50WN 645 from St Louis at the gate
19:45UA 4500 to Washington leaves the gate
6 h 55 apart on the timetable
The last days
WN 645 and UA 4500 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.