I still say that the fold-capable fighter at the end of Episode 5 is a VF-11 with FAST pack.
See exhibit A:
http://www.mahq.net/mecha/macross/plus/vf-11b-super.htm
If you compare it to the show from the end there, they have a VERY similar style of FAST pack, and the ailerons plus the swelling nosecone, which is unlike the rather straight nosecone of the VF-4 which didn't curve out a bit before tapering off again. Between that and the cockpit configuration, along with the fact that it's an OLD fighter... it'd be more useful as a courier than as a front-line fighter, especially compared to the newer VF-17's and VF-171's.