The Antonov An-225 Mriya(dream or inspiration), NATO reporting name: "Cossack" is a strategic airlift cargo aircraft that was designed by the Antonov Design Bureau in the Soviet Union during the 1980s. It is powered by six turbofan engines and is the longest and heaviest airplane ever built, with a maximum takeoff weight of 640 tonnes It also has the largest wingspan of any aircraft in operational service. The single example built has the Ukrainian civil registration UR-82060. A second airframe with a slightly different configuration was partially built. Its construction was halted in 1994 because of lack of funding and interest, but revived briefly in 2009, bringing it to 60%-70% completion. On 30 August 2016, Antonov agreed to complete the second airframe for Aerospace Industry Corporation of China (not to be confused with the Aviation Industry Corporation of China) as a prelude to AICC commencing series production.

The Antonov An-225, initially developed for the task of transporting the Buran spaceplane, was an enlargement of the successful Antonov An-124. The first and only An-225 was completed in 1988. After successfully fulfilling its Soviet military missions, it was mothballed for eight years. It was then refurbished and re-introduced, and is in commercial operation with Antonov Airlines carrying oversized payloads. The airlifter holds the absolute world records for an airlifted single-item payload of 189,980 kilograms, and an airlifted total payload of 253,820 kg. It has also transported a payload of 247,000 kg on a commercial flight.