One of the largest “planes” ever built, the KM was designed by Russia as a high speed military transport. Taking it’s first flight in 1966, the ekranoplan was later revealed to the world by American sky satellites which showed a strange aircraft bearing the letters “KM” on its fuselage. The CIA named it the “Kaspian Monster”, though KM actually referred to “Korabl maket” – “prototype ship” in Russian.
It is classified as an ekranoplan as opposed to an airplane because it uses an aerodynamic principle known as ground effect to fly 3-5 meters above the sea. Only one prototype was ever constructed, though the Soviets had planned to use a fleet to transport equipment, including nuclear weapons, around the Caspian Sea and Black Sea.
Documented a a marine vessel, the KM could reach speeds up to 400 mph. The KM was tested at the Caspian Sea for 15 years until a crash in 1980. The only model ever produced, the MD-160, was retired in the late 1990s and now sits rusting at a naval station in Kaspiysk.
Source: English Russia