A properly designed trike is as stable as a quad. Some trikes are claimed to have superior handling to quads and I have every reason to believe it.
I've got a homemade trike, ridden a VW trike, had the old trike ATVs, and taxid tricycle gear aircraft. There is nothing scary about a trike.
As far as flying up through the air upon hitting something: you've been watching CHiPS reruns haven't you!
I doubt that would be the behavior of it but even more importantly, how often do you engage in head-on collisions? Stay 3000 miles away from me, please.
Do you ever throw a leg over a bicycle or motorcycle? I guarantee you, in just about every traction-fail or impact situation, you will be better off on/in a trike than a bike.
That leaves the batteries, and I don't know much of anything about the spontaneous ignition of said l-ions. Were I hypothetically speaking an Aptera customer I probably would have wanted a gas or diesel version anyway (cold weather, long distance ops).