AS 354 then AS 407 at Seattle
Missoula → Seattle → Chicago O'Hare
Timetable, Seattle time
07:46AS 354 from Missoula at the gate
08:44AS 407 to Chicago O'Hare leaves the gate
58 min 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 354 and AS 407 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.