both ships are based off bill's unique fighter from the original 64! His fighter in the original game is very, very ugly. It has a flat, square canopy window and a very thin vertical tail segment. But stands out quite well when playing, due to its ventral fin. The upward cantered wings in this redesign really help separate it from the standard cornerian fighter! I love the thin silhouette. makes it look very fast. also has the double laser cannons, like it had in command. even though it only fires a single shot in game.

Looking at the N64 models on this site, Bill's fighter is missing for some reason. But if you beat the game having defeated the boss on katina, Bill's fighter will be flying in formation with the rest of the gang during the end cutscene. It lets you get a very good, close look at his hideous rig'

Also, the new game confirms Bill's unique fighter as the "cornerian fighter Mk. II" So we finally have a solid distinction between his fighter, and the standard models.

Fun fact: Bill's ship in this game was reused from Star Fox Command to make him stand out above the other Cornerian pilots in that level, which makes sense because Q-Games developed both games.