In this game, bombers fly faster and higher than they did in real life.
Note how it says "slow" bombers? Lumbering came to mind. They cruised during combat for maximum fuel conservation. They didn't firewall the engines with 25% gas at takeoff, make it to 35K inside 30 minutes, and the float above all opposition because they can't fly high enough to intercept.
They were low, slow, and targets. In this game they're almost god-like.