MF 2921 then VS 21 at Heathrow
Xiamen → London → Washington
Timetable, London time
10:30MF 2921 from Xiamen at the gate
13:20VS 21 to Washington leaves the gate
2 h 50 apart on the timetable
The last days
MF 2921 and VS 21 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.