Flying is one of those things... If you look at it strictly from an environmental point of view, it's burns a lot of fossil fuels and should be avoided. But if you look at it from other angles, it can be quite good.
Solar aviation is still in its infancy, but it's getting better all the time. We might never see big passenger airplanes being solar powered, but there's all kinds of other cool stuff that can be done with this technology.