BA 581 then AA 109 at Heathrow
Milan → London → Boston
Timetable, London time
14:35BA 581 from Milan at the gate
13:10AA 109 to Boston leaves the gate
22 h 35 apart on the timetable, overnight
AA 109 leaves 22 h 35 after BA 581 arrives on the timetable: more than half a day, so not a connection we count.