AA 3546 then AS 257 at Boston
St Louis → Boston → Seattle
Timetable, Boston time
13:44AA 3546 from St Louis at the gate
16:33AS 257 to Seattle leaves the gate
2 h 49 apart on the timetable
The last days
AA 3546 and AS 257 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.