Lithium polymer batteries are better for flying than lithium ion, they are lighter and can take a higher amp draw.
If your lost when it comes to lithiums let me try to help.
Li-poly cells are much lighter than nicds and nimh and have amazing capacities for their size( you can fly for 30 min instead of 3)
Li-poly cells are 3.7v per cell
Special skills are needed to make your own packs
You have to pick the right pack for your application or you will ruin the pack and possibly have a fire
You must have a special charger

I know that lithiums seem to have a lot of disadvantages but once you are set up and are past the learning curve you wil never want to use nimh, nicd, or fuel again.