A3 504 then JU 423 at Istanbul
Thessaloniki → Istanbul → Belgrade
Timetable, Istanbul time
16:55A3 504 from Thessaloniki at the gate
16:40JU 423 to Belgrade leaves the gate
23 h 45 apart on the timetable, overnight
JU 423 leaves 23 h 45 after A3 504 arrives on the timetable: more than half a day, so not a connection we count.