The Caspian Sea Monster was a secret Russian vehicle devloped during the cold war, a type of Ekranoplan or 'Ground Effect Vehicle'. They are a form of aircraft that fly a few meters above the surface, close enough that vortices cannot form under the wings. Very fast, stable and efficient. This one pictured had (has?) a lifting power of 1000 tonnes, could travel over 400km per hour and was effectively invisible to RADAR and SONAR, being above water but below the radar floor.
This is a badass plane or whatever it is...