Would those be aero mods for efficiency or for speed? Maybe downforce? Perhaps more lift wouldn't be a bad thing either
I'm playing with my Jetta's side profile in Photoshop and I've noticed one significant potential advantage that hatchbacks have over coupes with regards to aero modding. It seems like it is much easier to build and attach a boat tail to a hatchback. Having a trunk which does not naturally taper inwards at a 15 degrees gets in the way. It may be possible to build a boat tail hanging off the back of the trunk but otherwise I don't see any good way to boat tail a sedan, apart from extensive cutting and welding of the trunk itself and reorganizing the rear windshield support for a better angle.
Still, the Aptera is wide and rectangular right to the back edge, but it gets flatter as it approaches the tail lights and license plate.
It might be as simple as a flat spoiler over the rear edge of the trunk like the Ford 999 land speed racer. That should give the airflow lots of space to reattach and the flat, sharp rear edge should make for a clean final separation for a smaller wake than a normal rounded trunk lid edge.