The "barrel roll" (as dubbed by Peppy Hare in the English version of Star Fox 64) that appears in many Star Fox games is not a barrel roll at all, but rather an aileron roll. In the original Star Fox, the maneuver is generically referred to as just a roll. In Star Fox 64, Peppy's iconic phrase "Do a barrel roll!" was created by the English localization team; in the Japanese version, he instead says "ローリングで弾くんだ!", which translates to something along the lines of "deflect it with a roll!" It's only in Star Fox: Assault that you can actually perform a barrel roll.