Usually the engine is heaviest.
It is the An-225 with a 1.3 million pound takeoff weight it makes the worlds heaviest airplane.
The C-17. It is worthless
the spruce goose
Fully loaded the Knock Nevis Super Tanker is the heaviest ship every built.http://www.worldinterestingfacts.com/infrastructure/top-5-biggest-ships-ever-made-in-the-world.html
The Airbus A 390 is the heaviest aircraft in productionThe Airbus A 390 is the heaviest aircraft in production
An-225 with a 1.3 million pound takeoff weight
The Wright brothers made the first ever airplane December 17th 1903.
The biggest (and heaviest) spacecraft ever built is the International Space Station, which is still not quite complete (July 2011).
Large clouds are much, much heavier.
Their first fully practical airplane was built in 1905. (Their first powered, sustained and controlled airplane was built in 1903.)
George Cayley built the first glider, Clement Ader built the first self powered airplane, and Wilbur & Orville Wright built the first self powered and controllable airplane.