AC 748 then AA 2602 at Boston
Montréal → Boston → Los Angeles
Timetable, Boston time
09:48AC 748 from Montréal at the gate
14:25AA 2602 to Los Angeles leaves the gate
4 h 37 apart on the timetable
Boston’s board gives an arrival time for only about 58% of its flights, so many days show no gate time.
The last days
AC 748 and AA 2602 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.