It already happened to one of my planes a few years ago... the wings become fragile and break during a flight at a good altitude (= far from the ground). I bought this yellow plane almost 6 years ago. This is a good lifetime for a piece of light expanded plastic.
For those who like to see pictures:
I could glu the wings again together and fix the wood support puzzle inside but the wings would break again after some time.... micro fissure occur within plastic materials... anyway, i ll try to fix it ;)