Killing flies and repelling flies isn’t easy. Fly killing devices include the Fly bottle and fly swatter. Also the sticky glue board fly killer, and fly sticker are other options.
The fly bottle idea seems smart. Keep it indoors and consider taking it outside just while being used, unless it actually attracts more flies.
Natural fly repellent ingredients: It seems the same main scents that repel mosquitoes also repel flies. These ingredients include:
• Geranium Oil: to humans it lacks a strong smell
• Lemon Eucalyptus Oil (eucalyptus citriodora) smells a bit like vics.
• Lemongrass Oil
• Peppermint Oil
• Basil
• Marigolds: hardy garden plants