They didn't, at least in the sense of the massed formations seen in daylight attacks. Night bombers flew individually as part of streams to avoid the risk of collision. Darkness and electronic warfare countermeasures were the principal defenses, rather than massed firepower. Bomber Command by Max Hastings is a good resource if you're interested in Britain's night bombing campaign.

Carrots were disinformation. What enabled allied pilots to see better at night was the fact that their instruments were lit by red light, which doesn't destroy night vision.

They were told that their carrot diet was responsible simply to mislead the axis powers if they got interrogated on the subject...