Once, I discovered the perfect flyswat. It just so happened that after a long battle to get a fly to leave peacefully, the closest thing to hand was an empty plastic clothes basket. You know the kind, with lots of holes through all the sides.

In frustration I grabbed the basket and swatted the fly. It made an amazing "swoosh" sound, like swinging a pipe in Streets of Rage. I can only imagine the blind panic as the fly executed its usual escape manoeuvre, only to find that the object it attempted to dodge was less of a rolled-up newspaper, and instead the swat equivalent of a star destroyer.

Finally, a strike back for team human...

Opens window

Fly stays

30 of his cousins come in

So.. You have chosen genocide

you could remove half the walls on your house and that fly still wouldn't find its way out

Lol thats literally what I say to the flies. But my death/hit ratio is probably 0.3.

Tip: smack it with an open hand. It reduces air resistance, thus more hand speed, and reduces the pressure of the pocket of air between your hand and the surface that would push the fly out.

Is it not an option to leave the window open and give the fly some time?