maybe used compressed air to replace some battery mass, b/c compressed air tank lighter and cheaper (to run at least) than battery, plus the regenerative braking can be partially mechanically done for more efficient regenerative braking and less energy going in and out teh batter for longer battery life. maybe the compressed air can turn a generator which powers motors, or maybe it will be less emissions to run small diesel generator given it can have a much longer lifetime than current batteries. https://www.youtube.com/watch?v=ic6cRlyQ2rk https://www.riversimple.com/test-new/ https://www.riversimple.com/making-efficiency-profitable/ https://www.riversimple.com/technology-behind-rasa-hydrogen-car/
Compressed air has a very low energy volume density unfortunately. Although there are some useful use-cases to the idea, I think the battery electric works best in the Aptera.