Don't just think batteries though, fuel cells are catching up very fast too along with improvements in flexible solar cell technology and efficiency.
have a look at this link http://www.gizmag.com/yuneec-e430-elect ... aft/12036/ this is a small light aircraft that will fly for 2.5 hours on a single charge and takes 3 hours or so to recharge, claimed I add

Is this the future of small low cost aviation? could be? certainly I am finding it very interesting to consider with future travel needs
Viv