A3 629 then BA 633 at Athens
Luxembourg → Athens → London Heathrow
Timetable, Athens time
21:55A3 629 from Luxembourg at the gate
16:25BA 633 to London Heathrow leaves the gate
18 h 30 apart on the timetable, overnight
BA 633 leaves 18 h 30 after A3 629 arrives on the timetable: more than half a day, so not a connection we count.