AA 1934 then UA 3924 at San Francisco
Miami → San Francisco → Los Angeles
Timetable, San Francisco time
10:29AA 1934 from Miami at the gate
14:30UA 3924 to Los Angeles leaves the gate
4 h 01 apart on the timetable
The last days
AA 1934 and UA 3924 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.