DL 400 then DL 878 at Boston
San Francisco → Boston → Washington National
Timetable, Boston time
15:30DL 400 from San Francisco at the gate
20:05DL 878 to Washington National leaves the gate
4 h 35 apart on the timetable
Today
From the airport’s board at 15:29 Boston time
15:51DL 400 expected at the gate21 min late
20:05DL 878 due to leave, no estimate yet
4 h 14 between the gates, on these times
The last days
DL 400 and DL 878 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.