The "bomber gap" was the unfounded belief in the Cold War-era United States that the Soviet Union had gained an advantage in deploying jet-powered strategic bombers. Widely accepted for several years, the gap was used as a political talking point in order to justify greatly increased defense spending. One result was a massive buildup of the United States Air Force bomber fleet, which peaked at over 2,500 bombers, in order to counter the perceived Soviet threat. Surveillance flights utilizing the Lockheed U-2 aircraft indicated that the bomber gap did not exist. Realizing that mere belief in the gap was an extremely effective funding source, a series of similarly nonexistent Soviet military advances were constructed in a tactic now known as "policy by press release." These included claims of a nuclear-powered bomber, supersonic VTOL flying saucers, and only a few years later, the "missile gap."
The gap appears 
On February 15, 1954, Aviation Week published an article describing new Soviet jet bombers capable of carrying a nuclear bomb to the United States from their bases in Russia. The aircraft they referred to was the Myasishchev M-4 Bison. Over the next year and a half these rumors were debated publicly in the press, and soon after in the United States Congress.
Adding to the concerns was an infamous event in July 1955. At the Soviet Aviation Day demonstrations at the Tushino Airfield, ten Bison bombers were flown past the reviewing stand, then flew out of sight, quickly turned around, and flew past the stands again with eight more, presenting the illusion that there were 28 aircraft in the flyby. Western analysts extrapolated from the illusionary 28 aircraft, judging that by 1960 the Soviets would have 800.
At the time, the USAF had just introduced its own strategic jet bomber, the B-52 Stratofortress, and the shorter-range B-47 Stratojet was still suffering from a variety of technical problems that limited its availability. USAF staff started pressing for accelerated production of the B-52, but it also grudgingly accepted calls for expanded air defense. The Air Force was generally critical of spending effort on defense, having studied the results of the World War II bombing campaigns and concluding that Stanley Baldwin's pre-war thinking on the fruitlessness of air defense was correct: the bomber almost always did get through. Like the British, they concluded that money would better be spent on making the offensive arm larger, deterring an attack. The result was a production series consisting of thousands of aircraft. Over 2,000 B-47s and almost 750 B-52s were built to match the imagined fleet of Soviet aircraft.
The gap disproven 
The first U-2 flights started in 1956. One early mission, Mission 2020 flown by Martin Knutson on July 4, 1956, flew over Engels airfield near Saratov and photographed 20 M-4 Bison bombers on the ramp. Multiplying by the number of Soviet bomber bases, the intelligence suggested the Soviets were already well on their way to deploying hundreds of aircraft. Ironically, the U-2 had actually photographed the entire Bison fleet; there wasn't a single bomber at any of the other bases. Similar missions over the next year finally demonstrated this beyond a doubt, and at least in official circles the gap disappeared.
As it was later learned, the M-4 was unable to meet its original range goals and was limited to about 8,000 km. Unlike the United States, at that time the Soviets lacked overseas bases in the Western Hemisphere and therefore the M-4 would not be able to attack the US and land at a friendly airbase. Interest in the M-4 waned, and a total of only 93 were produced before the assembly lines were shut down in 1963. The vast majority of these were used as tankers or maritime reconnaissance aircraft; only the original 10 shown at the air show and nine newer 3MD13 models served on nuclear alert.
References in Popular Culture 
- In Stanley Kubrick's movie Dr. Strangelove, the notion of a "bomber gap" is parodied when the character of Buck Turgidson (a Pentagon general) declares that the United States "cannot afford a mineshaft gap" when discussing the use of mineshafts as nuclear fallout shelters.
- In Mark Brazill, Bonnie Turner, Terry Turner's U.S. TV Sitcom That '70s Show, "Who Wants It More", Donna and Eric are doing a report for school on the Arms Race between the U.S.S.R. and the U.S.A. in his bedroom. After several "study breaks" in which they make out, the two disagree over the "bomber gap." Donna suggests that the U.S.S.R. started the Arms Race with the "Bomber Gap," and Eric laughs the notion off as silly which ends his chances for more "study breaks."
- Pictures Reveal Reds' New "Sunday Punch", Aviation Week, 15 Feb. 1954, 12–13
- Congress Gets Red Plane Facts, Aviation Week, 22 February 1954, pp. 13–14
- Heppenheimer, T. A. (1998). The Space Shuttle Decision. NASA. p. 193.
- Guarding the Cold War Ramparts: The U.S. Navy's Role in Continental Air Defense
- Bomber Gap
- Lockheed U-2 mission history
- Interview with Martin Knutson
- Myasishchev 'Bison'