We had problems with lots of flies, horrid. I don't like the way fly tape looks so I got these. They work great
We got Rescue Fly Traps. They are wonderful. Here is a little info you can find them at amazon.com
Flies that get in the house do tend to fly from window to window. I suck them up from the windows with my canister vacuum. A portable/handheld vacuum is good too. In my experience, getting sucked into the vacuum tends to kill them.