The heaviest airplane ever built in human history is the Antonov An-225 Mriya. The Mriya (which means “Dream” in Ukrainian) is a transport aircraft designed and built by the Antonov Design Bureau in the Soviet Union (now Ukraine) in the late 1980s. The Mriya was built to transport the Buran, the Soviet Space Shuttle. It has a maximum takeoff weight of 1.4 million pounds (640 metric tonnes) and a maximum payload capacity of over 500,000 pounds (227 metric tonnes).
The An-225 features six engines, 32 wheels on its landing gear, and a wingspan of 88.4 meters (290 ft). It’s 84 meters (275 ft) long and 18 meters (59 ft) high, making it the largest and heaviest airplane ever built. It was first flown on December 21, 1988, and only one was built and it’s still operational today, it’s mainly used to transport oversized cargo, like large industrial equipment and even other aircrafts.
Due to its size and weight, the Mriya is capable of carrying extremely heavy and large cargo, such as tanks, locomotives, and even other aircraft. It has been used for various commercial and military purposes, including transporting parts for wind turbines, oil drilling equipment, and even humanitarian aid.