The weight for the mass of the passengers scales with the volume (m^3) while the area of the solar cells (and wing) to lift them scales with m^2. The typical so

The weight for the mass of the passengers scales with the volume (m^3) while the area of the solar cells (and wing) to lift them scales with m^2. The typical solution for human scale aircraft is to fly faster (higher stall speed) and extend the length of the fuselage. Unfortunately, that combination doesn't increase efficiency so you end up needing even more fuel (or area and weight for batteries and PV). The demonstrated PV aircraft are already pushing the lowest wieght, lowest drag wings with the highest efficiency PV and energy dense Batteries. This is a case where bigger is harder (not so with Zeppelins where structural material weight/stiffness scale to much larger sizes).