B6 8662 then UA 639 at Boston
Kansas City → Boston → Los Angeles
Timetable, Boston time
14:52B6 8662 from Kansas City at the gate
17:59UA 639 to Los Angeles leaves the gate
3 h 07 apart on the timetable
The last days
B6 8662 and UA 639 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.