BA 873 then DL 31 at Heathrow
Krakow → London → Atlanta
Timetable, London time
18:05BA 873 from Krakow at the gate
12:40DL 31 to Atlanta leaves the gate
18 h 35 apart on the timetable, overnight
DL 31 leaves 18 h 35 after BA 873 arrives on the timetable: more than half a day, so not a connection we count.