The VF-31 Siegfried is the protagonist variable fighter of the new show.
It is the mass production version of the YF-30 Chronos advanced prototype variable fighter that appeared in the Macross 30 Playstation 3 video game from 2013. However, unlike the Chronos the VF-31 has two built-in gunpods in its arms and forward-swept wings.
In real life it was designed by Kawamori Shouji for the show. Not to be confused with the U.S. Navy's Strike Fighter Squadron 31 ("VF-31").