Summary

simple but effective fly swatter-

Paddle obviously needs to be printed from a a flexible filament (TPU, TPEE)
I also printed mine with no top or bottom and 4 shells so it's all infill only with perimeters!
Handle is 2 parts, and fairly long. wil need to print on a 300mm or larger bed with them turned 45º generally. Both halves will fit this way
you'll need to glue together, and two M5 screws and nuts to hold the paddle

note, my handle never finished as we had a power glitch but it was enough to be usable, that's why you see the tad of infill in the handle)