While air travel is quicker and safer than driving, it's also louder. The continuous low-frequency drone of the engines is why some people invest in noise-canceling headphones. To help reduce that non-stop hum, researchers at North Carolina State University and MIT have developed a thin membrane to be inserted into the lightweight honeycomb structure of planes and helicopters. "At low frequencies – sounds below 500 Hertz – the honeycomb panel with the membrane blocks 100 to 1,000 times more sound energy than the panel without a membrane." said Yun Jing, an assistant professor of mechanical and aerospace engineering at NC State University. The 0.25mm-thick membrane would only add an additional six percent to the overall weight of the honeycomb structure of aircraft. While that doesn't seem like much, every ounce counts to airlines trying to maximize flight costs. It'll be on them to decide whether they'd rather save money on fuel or makes cabins a better place for passengers.