BA 1399 then BA 744 at Heathrow
Belfast City → London → Geneva
Timetable, London time
13:45BA 1399 from Belfast City at the gate
16:20BA 744 to Geneva leaves the gate
2 h 35 apart on the timetable
The last days
BA 1399 and BA 744 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.