the.com/crop duster

means A small low-flying airplane that sprays pesticides or fertilizer over farmland — or, by rude extension, someone who silently releases a fart in a crowded room and casually walks away from the blast zone.

from The literal term comes straight from farming: 'crop' (the harvest) plus 'duster,' a machine that dusts fields with pesticide powder or spray, flying low in sweeping passes. The slang sense is a 20th/21st-century joke riffing on that image — a person 'flies over' a room, releases their payload, and moves on before anyone can trace the source, just like the plane disappearing over the horizon.