In blitzkrieg, the attacking motorized infantry armies move quickly, and are helped by tanks and aircraft. Slower-moving enemy units are overrun or surrounded and are often captured with little fighting. The slower units often become disorganized and are not yet ready to fight when they are captured.
The strategy of was developed in the 1930s, but the Wehrmacht seldom called it blitzkrieg.
This method worked well early in World War II during the invasions of Poland and France. It was mostly successful in Operation Barbarossa. Later in the war, the Allies learned to defeat German blitzkrieg attacks by defence in depth and by attacking the flanks of the attackers with reserve forces.
The Blitz refers to the German bombing of Britain, particularly London, during World War II, which destroyed over a million homes and killed over 40,000 people. It was supposed to quickly destroy industry and morale to make the British pressure the government to end the war. The Blitz was in response to the British bombing of German cities by the Royal Air Force. The Blitz began in September 1940 and continued until May 1941.