AA 1948 then UA 3900 at San Francisco
Chicago O'Hare → San Francisco → Los Angeles
Timetable, San Francisco time
13:28AA 1948 from Chicago O'Hare at the gate
18:00UA 3900 to Los Angeles leaves the gate
4 h 32 apart on the timetable
The last days
AA 1948 and UA 3900 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.