OSHKOSH, Wisconsin — The Elektra One from PC-Aero is making its North American debut here at Airventure. The sleek electric single-seater is a prototype of the airplane designer Calin Gologan hopes will go into production next year. But Gologan’s main goal isn’t production, it’s developing a truly “modern” airplane. He believes that starts with energy autonomy.

Gologan’s goal in developing a modern airplane is to move beyond how an airplane might look modern yet still use the same decades-old propulsion system. Those old engines come with the same high operating costs that have been around for ...