Context: The introduction of the guided missile resulted in a significant shift in anti-aircraft strategy. Although Germany had been desperate to introduce anti-aircraft missile systems, none became operational during World War II. Following several years of post-war development, however, these systems began to mature into viable weapons systems. The US started an upgrade of their defences using the Nike Ajax missile, and soon the larger anti-aircraft guns disappeared. The same thing occurred in the USSR after the introduction of their SA-2 Guideline systems.

Question: Which weapon caused a major shift in anti-aircraft strategy?
Answer: guided missile

Question: Which company wanted to introduce missile systems during the second World War but was not successful?
Answer: Germany

Question: What missile did the United States upgrade their defences with?
Answer: the Nike Ajax missile

Question: The introduction of the Nike Ajax missile caused what to disappear?
Answer: the larger anti-aircraft guns

Question: The introduction of what caused the larger anti-aircraft guns to disappear in the USSR?
Answer: SA-2 Guideline systems