We've spoken in the past about wake turbulence: "a disturbance in the atmosphere that forms behind an aircraft as it passes through the air. It includes various components, the most important of which are wingtip vortices and jetwash." Some sources refer to it as wake vortex.
The sole example of the world's biggest operational aircraft, the Antonov An-225 Mriya, recently landed at Rzeszów in Poland, making its approach through thick low-level fog. As it passed over observers waiting for it on the outskirts of the airfield, its enormous size generated enough wake turbulence to completely clear a path through the fog behind it, showing very clearly why it's dangerous to fly too close behind such super-large aircraft.
Wake vortex separation is a standard applied by air traffic control to regulate how far behind such aircraft others may safely fly. The bigger the aircraft, the greater the safety distance required. For example, a small aircraft following something like the An-225 would have to maintain a minimum separation of no less than 8 nautical miles (approximately 9.2 standard miles or 14.73 kilometers) behind it. Looking at that video, one can understand why!