AA 2553 then AA 490 at Philadelphia
San Francisco → Philadelphia → Chicago O'Hare
Timetable, Philadelphia time
17:14AA 2553 from San Francisco at the gate
21:02AA 490 to Chicago O'Hare leaves the gate
3 h 48 apart on the timetable
The last days
AA 2553 and AA 490 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.