I?m wondering if somebody could help me with a good idea about how to solve this problem. I finished my ailerons and one of them is a little bit bended in the middle off the trailing edge. If you look the trailing edge the shape is curved in the middle a little bit.

Many thanks
 
A little is ok...

There is no practical fix that I know of. 1/16"-1/8" is pretty common and will never be noticed. You could probably get away with even more. Move on and and keep building.