For anyone that has experience with various types of fliers like this, why does battery life suck so much and are there any options that can be used to extend it very significantly? Is it a matter of needing to invent better batteries, would reducing weight be the best option, or does it need to run off of some different fuel source to improve?

I guess my question really is: will this improve over time, or is there some real stumbling block that's holding that back?