ET 574 then BR 645 at O'Hare
Rome → Chicago → Taipei
Timetable, Chicago time
07:40ET 574 from Rome at the gate
12:10BR 645 to Taipei leaves the gate
4 h 30 apart on the timetable
The last days
ET 574 and BR 645 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.