AA 1998 then AA 946 at Philadelphia
Cleveland → Philadelphia → Denver
Timetable, Philadelphia time
07:29AA 1998 from Cleveland at the gate
11:24AA 946 to Denver leaves the gate
3 h 55 apart on the timetable
The last days
AA 1998 and AA 946 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.