The 1960 "U-2 incident" revealed what the Soviets had claimed for years, that the US was violating Soviet airspace with covert spy missions. But the breadth of the so called “ferret flights” remained a state secret that only started to emerge decades later. Many of those flights were made in a special reconnaissance version of the Boeing B-47 Stratojet.
The first class of nuclear submarines were a learning experience for the Soviet Navy. The November class boats experienced numerous difficulties and accidents, culminating in what has been described as a potential “Underwater Chernobyl."