Here is the UK, our window and doors are not made to easily accept a fly screen. It's seems our planning people and architects don't readily accept that, in some urban / countryside areas, we have more than one or two flies.
Where I live, right outside my back yard / garden, grows many trees. It's warm and damp in amongst those trees, animals live there, leave their daily activities behind, and some die there. Leaving the almost perfect breeding ground for flies!
My kitchen door leads right out to that.
Our houses are also not built with air conditioning already installed and it's rather expensive to have installed.
With this in mind, and because it's been unusually warm here of late, it's was not possible to open windows and doors to get air in the house, without these little beasties paying unwanted visits - I needed screens.
The image above shows the fly screen on the back door, prior to the clean up and the addition of a door closer.
The windows had a frame made from 2" x 1" batten to fit inside the window. This was covered in a fine mesh to keep out the flies, it also, unfortunately, had to be covered in 1cm squared metal fine wire, this was to keep out the neighbours cats.
These are not fixed. They are wedged in so they can be removed, from inside, to open and close the windows. A little annoying, but it works.
The door was made by a carpenter. We had 2" x 2" wood for the frame, the poor carpenter had to work with what I could think of, this frame was fixed outside of my back door frame.
The door was made with the remaining 2" x 1" batten left from the windows. It was made with stabilising bars across the middle and reinforced with metal work on the corners.
Again, covered in fine mesh and the very bottom of the door also has a panel of wire mesh for the cats. I've noted that there is stronger fine fly net out there, but the budget does not allow today, this will be added at a later date.
A suitably coloured wood preservative was used to blend it in with the brickwork of the house.
An automatic door closer was added as a reminder the ensure that the door needs to be closed at all times to be effective.
So far so good