AA 2156 then AC 3966 at Newark
Phoenix → New York → Chicago
Timetable, New York time
05:43AA 2156 from Phoenix at the gate
15:30AC 3966 to Chicago leaves the gate
9 h 47 apart on the timetable
The last days
AA 2156 and AC 3966 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.