AA 1639 then WN 1121 at San Francisco
Miami → San Francisco → Los Angeles
Timetable, San Francisco time
23:59AA 1639 from Miami at the gate
06:40WN 1121 to Los Angeles leaves the gate
6 h 41 apart on the timetable, overnight
The last days
AA 1639 and WN 1121 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.