AA 2603 then AA 4778 at Houston
Chicago → Houston → Philadelphia
Timetable, Houston time
10:15AA 2603 from Chicago at the gate
14:25AA 4778 to Philadelphia leaves the gate
4 h 10 apart on the timetable
The last days
AA 2603 and AA 4778 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.