The record for the highest Maximum Takeoff Weight (MTOW) of any aircraft ever built belongs to the Antonov An-225 Mriya, which had a staggering MTOW of 640 tonnes (1.41 million pounds). This six-engine Ukrainian monster was originally designed to carry the Soviet Buran space shuttle and held over 200 world records. In the world of active passenger aviation as of 2026, the Airbus A380-800 holds the top spot with a maximum takeoff weight of 575 tonnes (1.27 million pounds). To put this in perspective, a fully loaded A380 weighs roughly the equivalent of 100 adult African elephants. The Boeing 747-8 follows closely with an MTOW of about 448 tonnes. Reaching these massive weights requires immense thrust and specialized "heavy" runways; for example, the An-225 required 32 wheels in its landing gear assembly just to distribute its enormous weight and prevent the aircraft from crushing the tarmac. While the original An-225 was destroyed in 2022, it remains the engineering benchmark for the "heaviest thing to ever fly."