The biggest hero in all of Star Wars? Given the huge part he's played in the downfall of the Empire, and the lives he's saved along the way, it's hard to argue with saying it's R2-D2 (and, dammit, he's still the best droid in the galaxy, as much as I love BB-8). This is taking place before A New Hope, and thus before Luke Skywalker, so Artoo would be under the ownership of Bail Organa and thus a part of the Rebel Alliance. He's such a key figure in the Star Wars universe, and fits in the timeline, that it would make sense for him to have an appearance of some sort, even if he doesn't see any X-Wing action as such. That being said, though, if you're flying into battle in an X-Wing, who better to have by your side than the astromech?
NCTJ-qualified journalist. Most definitely not a racing driver. Drink too much tea; eat too much peanut butter; watch too much TV. Sadly only the latter paying off so far.
A mix of wise-old man in a young man's body with a child-like wonder about him and a great otherworldly sensibility.