AA 3977 then AA 1201 at O'Hare
Detroit → Chicago → Miami
Timetable, Chicago time
14:05AA 3977 from Detroit at the gate
14:38AA 1201 to Miami leaves the gate
33 min apart on the timetable
The last days
AA 3977 and AA 1201 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.