Aircraft noise pollution could be dampened with design based on owl wings

https://eandt.theiet.org/content/articles/2022/01/aircraft-noise-pollution-could-be-dampened-with-design-based-on-owl-wings/

"Nocturnal owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing configuration... Moreover, when the owl catches prey, the shape of the wings is also constantly changing... The team used noise calculation and analysis software to conduct a series of detailed theoretical studies of simplified aerofoils with characteristics reminiscent of owl wings"

Related: Toroidal propellers: A noise-killing game changer in air and water

https://newatlas.com/aircraft/toroidal-quiet-propellers/