FR 3073 then FR 4585 at Barcelona
Prague → Barcelona → Porto
Timetable, Barcelona time
11:15FR 3073 from Prague at the gate
15:00FR 4585 to Porto leaves the gate
3 h 45 apart on the timetable
The last days
FR 3073 and FR 4585 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.