China's first aircraft carrier, Varyag, an upgraded version of a partially built vessel purchased from Ukraine in 1998, is currently undergoing sea trials.
The US Department of Defense said the ship was expected to be relaunched as a platform for training pilots.
The upgrades were provided to the vessel's living and working compartments, engines, navigation systems, power-generating equipment, elevator and flight deck.
The Varyag is a ski jump-style carrier with a displacement capacity of 55,000t, around half that of the Japan-based US carrier George Washington, which has a displacement of 100,000t.
China has bought Russian SU-33 carrier-based fighters and has modified domestic J-11 jets for carrier landings and take-offs.