The biggest Air Plane in the world is “Antonov An-225 Mriya”. This biggest operating aircraft is belongs to Ukraine and designed to airlift the Energia rocket’s boosters and the Buran space shuttle for the Soviet space program. This Plane can carry 250 tons of cargo in one way trip. The Maximum speed of this Aircraft is 850 km/h.

Source: http://www.mostbeautifulpages.com