AS 3166 then AS 421 at Seattle
Portland (Oregon) → Seattle → Denver
Timetable, Seattle time
13:19AS 3166 from Portland (Oregon) at the gate
13:59AS 421 to Denver leaves the gate
40 min 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 3166 and AS 421 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.