The Soviet Union tried to develop a flying submarine during World War II. The design could have operated at 150 knots in the air and 3 knots in the water. Metal plates sealed the engines shut. At the Naval Engineering Institute, a flying submarine project was headed by engineer Boris Ushakov. In 1939 the project was temporarily suspended and classified. In 1943, on the orders of NKVD chief Lavrenti Beria, the project was resumed. In 1947 the first test of the flying submarine was performed. In 1953, the project was closed by order of Communist Party First Secretary Nikita Khrushchev. The design never "got off the ground".