AS 2129 then DL 3997 at Seattle
Calgary → Seattle → Portland (Oregon)
Timetable, Seattle time
09:06AS 2129 from Calgary at the gate
19:35DL 3997 to Portland (Oregon) leaves the gate
10 h 29 apart on the timetable
Seattle’s board gives a departure time for only about 57% of its flights, so many days show no gate time.
The last days
AS 2129 and DL 3997 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.