The Huey 204 was a type of rotary-wing aircraft, or helicopter, utilized on Earth during the latter half of the 20th century. Plexicorp owned a Huey 204 in 1986.
While attempting to construct a whale tank in the cargo bay of the Klingon Bird-of-Prey HMS Bounty, Sulu discovered a Huey 204 in the Plexicorp yards, a ship which he had a nostalgic admiration for, describing it as like something he flew "in his Academy days."
Sulu was able to borrow the Huey to carry the enormous panes of Plexiglass that Scott and McCoy procured across San Francisco.
Upon his return to the helm of the Bounty, Sulu had difficulty remembering how to fly the Bird-of-Prey after becoming accustomed to flying the Huey. (Star Trek IV: The Voyage Home)
The official designation for a Huey is UH-1 Iroquois. The nickname "Huey" is derived from the ships early designation of "HU-1", which stood for "helicopter utility." An early version of the script described this aircraft as a "Huey 205", which was a larger, upgraded version of the 204. [1]