Query: At what event was the Vostok spaceship first displayed to the public ?
Context: The Soviets kept the details and true appearance of the Vostok capsule secret until the April 1965 Moscow Economic Exhibition, where it was first displayed without its aerodynamic nose cone concealing the spherical capsule. The "Vostok spaceship" had been first displayed at the July 1961 Tushino air show, mounted on its launch vehicle's third stage, with the nose cone in place. A tail section with eight fins was also added, in an apparent attempt to confuse western observers.