Armada is a fan-coined name for a robot who appears very briefly in the reformatting scene of Transformers: The Movie.
In this scene, at least six Decepticons are rebuilt. Skywarp and Bombshell (or an Insecticon clone of him) become seemingly-identical robots, one of whom is Cyclonus. Unicron's monologue refers to "Cyclonus, the warrior...and his armada..."
Some fans have taken to calling the second Cyclonus-like robot by the name "Armada". We never again see two Cyclonuses after the newly-created Decepticons head towards Galvatron's ship.
Although it can be fun to speculate on the nature of this "new" character, it is certain that there was never meant to be a duplicate Cyclonus by this name. The script for the movie reads,
- CYCLONUS is CREATED and then his "armada" of similar, but smaller and similarly colored and clad creatures are formed.
This, and the lack of capitalization in Unicron's line of dialogue, above, make it clear that the writers of the film did not intend for this to be a character, but rather intended for Cyclonus to have a fleet of ships much like Scourge has his Sweeps.