The Geonosian Warrior is an Aircraft that is unique to the Confederacy, and is available at the Fortress in Tech Level 3. It can attack both land and air targets, but is most effective against Troopers.
In Tech Level 4, it can be upgraded to the Elite Geonosian Warrior, which has slightly improved movement speed and attack rate.
"Geonosian Warriors are members of the soldier caste of the species that teems beneath the surface of the planet Geonosis. The winged Troopers can engage both ground and air forces in close combat, although their strength lies in defeating other Troopers. Only the Confederacy has access to these unique insect-like units."
Despite being described as a Trooper in the manual, it's actually classified as an Aircraft in-game.