Here’s the fundamental problem: they designed the car backwards.
When you begin the design of any piece of technology, from cars to medicine to software, you begin with the functionality it will provide. A piece of technology allows you to do something you could not do without it. In technology, form always follows function.
They began with the idea of producing a vehicle that used a minimal amount of fuel. Hooray! Unfortunately, people don’t buy cars to save fuel. They buy cars to accomplish specific transportation tasks. If the car can’t perform the task, then it is useless, even if it is powered by perpetual motion.
The Aptera cannot function as a car because its design only allows it to move two people under ideal conditions of weather and road surface. Small two-seater cars have been around since the 1890s, but they never catch on beyond single 20-somethings because people use their cars to move people and stuff in many different configurations. The fuel-saving aerodynamics of the car destroys all the internal space that people can use to move all kinds of things. Its three-wheel design means that even if it did have space, it would be sensitive to load balance. The design also will not function under adverse conditions. Its ultra-light body will not provide sufficient traction in heavy rain, ice or snow. High crosswinds will knock it about and could even flip it. The hybrid motor will not provide a enough heat to keep people warm in a northern winter, nor will it provide enough power to run an air conditioner to keep people cool in a southwestern summer.
In short, you can’t actually use the Aptera as a real-world car. You can’t use it to replace a humble vehicle like a Toyota Camry or a Ford Escort. You can use it to move two people over short distance in the tranquil conditions of coastal California, but that is about it.