IB 344 then IB 547 at Madrid
Chicago → Madrid → Porto
Timetable, Madrid time
09:55IB 344 from Chicago at the gate
15:40IB 547 to Porto leaves the gate
5 h 45 apart on the timetable
The last days
IB 344 and IB 547 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.