AA 4397 then AA 3324 at Boston
New York JFK → Boston → Chicago O'Hare
Timetable, Boston time
23:44AA 4397 from New York JFK at the gate
05:54AA 3324 to Chicago O'Hare leaves the gate
6 h 10 apart on the timetable, overnight
Boston’s board gives an arrival time for only about 58% of its flights, so many days show no gate time.
The last days
AA 4397 and AA 3324 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.