The bomber gap was the Cold War belief that the Soviet Union's Long Range Aviation department had gained an advantage in deploying jet-powered strategic bombers. Widely accepted for several years by US officials, the gap was used as a political talking point in the United States to justify a great increase in defense spending.
One result was a massive buildup of the US Air Force bomber fleet, which peaked at over 2500 bombers to counter the perceived Soviet threat. Surveillance flights by the U-2 aircraft indicated that the bomber gap did not exist.