CS 633 then BA 721 at Zurich
Skopje → Zurich → London Heathrow
Timetable, Zurich time
10:45CS 633 from Skopje at the gate
19:20BA 721 to London Heathrow leaves the gate
8 h 35 apart on the timetable
The last days
CS 633 and BA 721 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.