U2 2533 then U2 6842 at Zurich
London Luton → Zurich → Porto
Timetable, Zurich time
20:25U2 2533 from London Luton at the gate
16:50U2 6842 to Porto leaves the gate
20 h 25 apart on the timetable, overnight
U2 6842 leaves 20 h 25 after U2 2533 arrives on the timetable: more than half a day, so not a connection we count.