in reference to a bit of wire mesh on a handle, 1917, from fly (n.) + agent noun from swat (v.). Simple swatter was used in this sense by 1906. Other older names for similar implements were fly-duster (1860), fly-whisk (1836), fly-brush (1823), fly-fan (1821), fly-flap (mid-15c., glossing Latin muscarium).
1. His inspiration to fly came even before he joined the Army.
2. Then the woodcutter let his axe fly— Thwack! Everyone heard it.
3. It was all pretty much done on the fly.
4. Steve Crabb can fly the flag with distinction for Britain in Barcelona.
5. You can fly direct to Amsterdam from most British airports.