Flies. Can anyone offer any advice on strategies?

Evening,

I've never posted here before so don't know whether this is appropriate but I am in desperate need of some help forming strategies to aide my 8 year old daughter with her outright terror of flies.

The sun is shining which is great news for most of the world but I'm afraid a certain gut stirring dread is attached to the warm summer rays in our household. The fear is very real and very consuming. All windows and doors must be shut and any family member being outside the house can spark a tremendous melt down. The strange thing is that although the fly fear is ever present in our lives, it is much, much worse when we're at home. 

Has anybody experienced this either as a parent or has anybody had these fears themselves? Any help that can be offered would be greatly appreciated.

Many thanks in advance.