AA 436 then DL 2889 at Boston
Charlotte → Boston → Seattle
Timetable, Boston time
09:17AA 436 from Charlotte at the gate
15:47DL 2889 to Seattle leaves the gate
6 h 30 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
AA 436 and DL 2889 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.