AA 547 then UA 545 at O'Hare
Boston → Chicago → Philadelphia
Timetable, Chicago time
15:29AA 547 from Boston at the gate
19:45UA 545 to Philadelphia leaves the gate
4 h 16 apart on the timetable
The last days
AA 547 and UA 545 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.