You might want to consider using a larger aircraft like a bomber, instead of a fighter. Bombers tended to have multiple gun turrets; this would allow you to attack multiple party members in different directions. If you do this, you might want to use an idea that ... well, somebody (I don't recall who) on this forum suggested for making more challenging enemies, and that is to stat it as multiple foes that share the same body. In this case, you'd have one 'main' bad guy (the aircraft body) who is VERY tough and could move around and do slam attacks or wings slashes or whatever you decide on. In addition, there would be a couple of 'secondary' bad guys representing the turrets. They can each, independently, make attacks with their weapon. And even though they are 'part of the aircraft', I'd make it so that they are targetable independently (aimed shot!) and more easily damaged.
So they fight might start off with the aircraft charging random party members (maybe make these awkward attacks, requiring a maneuver to line up and allowing the characters the opportunity to maneuver out of the way), while the guns either target different random characters or do sprays. The players maneuver out of the way of the big guy while destroying the turrets. Once the turrets are out, the aircraft takes to the sky ... and perhaps starts dropping bombs. These should be fairly inaccurate, but do some hurt if they hit.
As for your werecat's last hurrah ... well, the scene I have in my mind her clawing her way onto (or even into) the bomber as it takes off, then confronting the spirit inside (or just inflicting damage to the frame from within). This might serve to distract the bad guy (helping the bombs miss more) and dealing damage that bypasses its toughness (The Catch: attacks from within?). She will, of course, die in the resulting crash, but will be instrumental in taking the thing out.