Great, it's a plane that can fly using solar power. Due to it's current design, in itself is it very useful? Maybe recreationally. Commercially? Naw. However it does open the path for better solar technolgies, including for cars, homes and other devices.
If all goes well it proves that solar technology can be a very viable and renewable resource that's worth investing in, even if it never makes it to huge commercial planes (That might not always be the main method of travel at large distances down the road anyway, seen the rate technology increases.) Power is already fairly cheap, in north america anyway; but soon we could have such an abundance that we no longer pay for electricity (Monthly anyway). As solar panels becomes cheaper and more widely used as they become more effective, we could see alot more people off grid, until it becomes a design standard for houses not to require grid power except during excessive lack of sunlight, or even just to reduce the power load on our not so renewable sources of power.
These people right here are at the heart of this advancement. I hope the best for this as twenty years ago even the idea would be completly scoffed at. You want me to invest in a plane that can fly just off of light from our sun....