I use Vapona window stickers. They're a sunflower shaped and coloured sticker that you put on the window, top corner is ideal, they are unobtrusive and not at all unsightly. The stickers contain a chemical that, when flies land on them, kills the flies. We have sat in the lounge and watched this happen, it literally takes just a few minutes to take effect. The flies are attracted to the "flower" and die very soon afterwards! No nasty fly sprays either.
Good Morning Wednesday 1st May May Day
After marriage, life with spouse is different than promised