YF-19 "Double Nuts" is a prototype variable fighter from Macross Plus, not a human character. It is one of the advanced test aircraft developed for the New UN Spacy’s next-generation fighter competition, competing against the YF-21. Piloted primarily by Isamu Dyson, the YF-19 is known for its speed, agility, and cutting-edge design. It plays a central role in the series’ aerial battles and symbolizes the rivalry, innovation, and risk surrounding experimental military technology.