Avro Lancaster
The Lancaster was arguably the most successful bomber of WWII, carrying a large payload deep into enemy territory.  Unlike the USAAF bombers who were tasked with daylight bombing and the hazards that came with that, Bomber Command of the RAF favoured the relative safety of night time raids. This was of course not the case, the German airforce became highly skilled at night fighing and developed some extremely effective strategies as well as weaponry in their attempt to defeat the night threat.