AA 540 then UA 2329 at O'Hare
Nashville → Chicago → Hartford
Timetable, Chicago time
11:05AA 540 from Nashville at the gate
15:00UA 2329 to Hartford leaves the gate
3 h 55 apart on the timetable
The last days
AA 540 and UA 2329 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.