In order to comply with the GoFly Prize guidelines, the Zero must fit within an 8.5-foot sphere. 
The design of the Zero maximizes wing area and stays just below the space requirement by having a wing that measures just under 8.5-feet.  This is small compared to many of the eVTOLs currently being developed.  The KittyHawk Flyer sponsored by Larry Page, for example, measures 8′ by 13′ making it difficult to fit inside a garage bay or land on top of a small building.  The Boeing Passenger Air Vehicle (PAV) that was in the news earlier this year for its first flight measures 30′ by 28′.  It is clearly designed with other goals in mind as it could not land in your cul-de-sac.  As the competition approaches, the Zero will continue to keep the needs of the individual wanting a personal air vehicle in mind.