Russia had the crazy idea of building an aircraft that would refuel by submarine
During the mid-1950s, the Soviets fooled the U.S. into believing that they had hundreds of Bison bombers ready to deploy, but in reality they still lacked a way of reaching the U.S. mainland.
Their solution to this problem was the Bartini-57, a long-range strategic bomber that could land on water and refuel by submarine mid-way through its mission. The aircraft was the brainchild of Italian designer Robert Ludvigovich Bartini, who built some of Russia's most advanced aircraft between the 1920s and 1950s.
But Bartini's bomber was cancelled when Sputnik was launched in 1957 by his protegé, Sergei Pavlovich Korolev. The Soviets would then set their sights on missiles rather than bombers, which triggered the Space Race, according to this video.