AA 2196 then UA 2318 at Houston
Philadelphia → Houston → St Louis
Timetable, Houston time
11:34AA 2196 from Philadelphia at the gate
14:40UA 2318 to St Louis leaves the gate
3 h 06 apart on the timetable
The last days
AA 2196 and UA 2318 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.