AS 354 then WN 8549 at Seattle
Missoula → Seattle → Denver
Timetable, Seattle time
07:46AS 354 from Missoula at the gate
11:35WN 8549 to Denver leaves the gate
3 h 49 apart on the timetable
Seattle’s board gives a departure time for only about 59% of its flights, so many days show no gate time.
The last days
AS 354 and WN 8549 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.