Near the conclusion of the Clone Wars, the Galactic Republic employed a BTL-B Y-wing fighter-bomber. This BTL-B Y-wing starfighter/bomber was stationed on the Venator-class Star Destroyer Tribunal when Order 66 was executed. This directive prompted the clone troopers onboard to betray Ahsoka Tano, a former Jedi Padawan. Subsequent to Tano's freeing of Rex, a Clone Commander, from his inhibitor chip, the pair attempted to flee the Tribunal. The vessel was on a collision course with a moon after Darth Maul, previously a prisoner on the starship, sabotaged its hyperdrive. Maul commandeered the shuttle intended for Tano and Rex's escape, compelling them to locate the starfighter in the repair bay amidst enemy clone fire, resulting in a perilous and close escape.
Following the reorganization of the Republic into the Galactic Empire, Rex persisted in utilizing the Y-wing to oppose the new authority. He encountered the former clone commandos of the Bad Batch on the junkyard planet Bracca. Their purpose was to employ the medical resources within a derelict Star Destroyer to eliminate the Batch's inhibitor chips. Rex piloted the Y-wing to land within the remnants of another vessel. Upon the Bad Batch's arrival, they positioned their transport, the Marauder, adjacent to the Y-wing before disembarking to accompany Rex to their objective.
This [starfighter](/article/starfighter], a BTL-B Y-wing starfighter/bomber, was powered by twin ion jet engines. Its offensive capabilities included two forward-facing laser cannons and a rotating SW-4 ion cannon managed from the gunner's station. The craft featured retractable legs for ground landings. Spanning 23.4 meters, the bomber accommodated a crew of three: a pilot within the cockpit, a gunner in the central bubble turret, and an astromech droid housed in the rear socket, behind the gunner's turret. The cockpit, accessible via a three-sectioned hatch, provided controls for activating the starfighter's engines and deploying the gunner's turret. The Y-wing's primary white color scheme was accented with blue stripes along its central structure and grey markings extending the length of the engines, which also displayed the Republic crest in black.
During the latter stages of the Clone Wars, a conflict between the Galactic Republic and the Confederacy of Independent Systems, the Galactic Republic Navy deployed the Y-wing. In 19 BBY, this Y-wing was part of the Tribunal's complement. The Venator-class Star Destroyer was positioned above Mandalore shortly after the conclusion of the recent siege. In this battle the Mandalore resistance and the forces of the Grand Army of the Republic overcame the Shadow Collective and captured its leader, the rogue Sith Lord Maul. The Tribunal, under the command of Ahsoka Tano and Rex, was tasked with transporting Maul to the Jedi High Council on Coruscant. The Y-wing was docked in the Tribunal's repair bay, above an exit in the capital ship's lower hull. It was also the only ship not undergoing maintenance at the time.
However, shortly after the Tribunal entered hyperspace, Darth Sidious, the Dark Lord of the Sith, initiated Order 66. This command compelled the clone troopers of the Grand Army to turn against and kill their Jedi Generals via inhibitor chips implanted in their brains. Tano was forced to flee within the ship, releasing Maul from detention as a diversion before liberating Rex from brainwashing with the assistance of three astromech droids, including her former unit R7-A7. With Rex freed, they sought to escape the Star Destroyer. However, the escape pods were destroyed due to Rex's brainwashed orders, forcing them towards the hangar in hopes of stealing a shuttle.
Maul, now free, destroyed the Tribunal's hyperdrive, causing the cruiser to exit hyperspace and enter a collision course with a moon. Upon reaching the hangar control room, Tano and Rex discovered the ship's fate and that the clone troopers, led by CT-5597 "Jesse", a Clone Lieutenant and ARC trooper, had gathered to prevent any escapes. Observing Jesse and his men positioned atop the lifts to the repair bay, Tano devised a plan to facilitate their access to the shuttle by directing most clones to the maintenance level. However, while Tano and Rex fought off the remaining clones, Maul appeared and stole the Nu-class attack/transport shuttle from bay 12 that they planned to use. Tano could not stop Maul's escape, as Rex was in danger of being overwhelmed by clone reinforcements. She created a hole in the floor, dropping herself and Rex to the repair bay while droids RG-G1 and CH-33P raised the lifts before the clones destroyed them.
Tano and Rex sought an alternative escape vessel but found most ships in maintenance and thus unflyable. After eliminating the remaining clones in the bay, Tano spotted the Y-wing in its docking port and alerted Rex. They fought off more clones before heading toward the starfighter, but the lifts began to descend as Jesse's forces gained control. As Tano defended against blaster fire, Rex ran to the Y-wing, urging Tano to get him there. Reaching the edge of the hole, Tano used the Force to propel him across the gap to the fighter, where he grabbed on as Tano focused on the clones' fire. Climbing onto the bomber, Rex stunned attacking clones before opening the cockpit hatch and entering.
By then, the Tribunal had entered the moon's atmosphere, and the command bridge exploded, killing the officers and rendering the ship uncontrollable. The clones and Tano lost their footing, and Rex, seeing the situation, took the pilot's seat and called for Tano to reach the Y-wing. Tano leapt for the starfighter, but it was dislodged and thrown into the debris field behind the doomed Star Destroyer, leaving Tano falling. Rex activated the Y-wing after a struggle, regaining control and flying back towards the Tribunal. He searched for Tano, opening the gunner's hatch when he located her. Tano grabbed the hatch but lost her grip and was thrown again. As Rex pursued her, she slowed herself by running along a detached ion engine, successfully boarding the Y-wing after leaping off it. Rex steered the starfighter away from the crash, and he and Tano watched the Tribunal fall beneath the clouds.
Tano and Rex landed the Y-wing at the crash site, salvaging R7-A7's remains and other useful items, and burying the dead, as no one else survived. As Tano spent a final moment at the graveyard, Rex returned to the fighter and stowed a shovel in a rack on its side, then turned back to Tano.
After departing the moon, Tano learned of Padmé Amidala's death. Tano and Rex traveled to Naboo, Amidala's homeworld, so Tano could attend her funeral. Landing the starfighter in a river valley near Theed, Rex stayed with the ship while Tano was gone. At the funeral, Bail Organa spotted Tano, surprised she had come despite the danger. When Organa asked about her ship, she said it was by the river. Organa gave Tano a comlink to contact him with before they parted, Tano evading shock trooper patrols before returning to the ship, whereupon she and Rex left Naboo.
Tano and Rex separated to hide from the new Galactic Empire. The repaired R7 ended up with Trace and Rafa Martez, two sisters Tano had met after leaving the Jedi Order. Rex kept the Y-wing and began opposing the Empire. With the sisters' help, Rex tracked down Clone Force 99, rogue clones immune to their inhibitor chips, and had them meet him on Bracca to surgically remove them in a wrecked Venator. He landed the Y-wing in a wrecked hangar near the target ship in Bracca's starship graveyard, with the "Bad Batch" landing their shuttle Marauder next to the starfighter upon arrival. After the surgeries, Rex parted ways with the squad to rendezvous with a contact.
Following the establishment of the Galactic Empire, Captain Rex owned and operated the Y-wing.
The Y-wing made its debut in the Star Wars: The Clone Wars series finale, "Victory and Death."