AA 78 then BA 802 at Heathrow
Dallas-Fort Worth → London → Reykjavík
Timetable, London time
12:10AA 78 from Dallas-Fort Worth at the gate
11:45BA 802 to Reykjavík leaves the gate
23 h 35 apart on the timetable, overnight
BA 802 leaves 23 h 35 after AA 78 arrives on the timetable: more than half a day, so not a connection we count.