Wait wait wait, this gives me an idea of why the Banished have some funky looking stuff. They're re-purposing and adding UNSC tech to existing covie gear. Put some Pelican armor plating on banshees, building completely new vehicles out of covie and UNSC scrap, this faction is stuck on the Ark which is probably full of old broken UNSC and Covenant stuff from the battle there, so the new design is them making do with what they have at hand.