BA 757 then KL 9936 at Heathrow
Basel → London → Amsterdam
Timetable, London time
15:15BA 757 from Basel at the gate
18:30KL 9936 to Amsterdam leaves the gate
3 h 15 apart on the timetable
The last days
BA 757 and KL 9936 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.