“The noise during a typical plane journey can vary significantly. Take-off and landing are the loudest moments, when noise levels inside the cabin can reach 105 decibels (dB). At cruising altitudes, noise drops to around 85 dB, says Pamela Mason of the American Speech-Language-Hearing Association (ASHA). Long exposure to 85 dB can cause temporary hearing problems. “Many people notice tinnitus – ringing in the ear – following a long flight, an early symptom of noise damage,” says Mason. And if noise goes higher than 90 dB for eight or more hours per day, it may lead to permanent hearing loss, warns the US Federal Aviation Authority (FAA). On older aircraft, or towards the back of a plane, noise levels can often get close to this threshold.”

BBC - Future - How to cut noise in a plane cabin

Full disclosure: I don’t cover my ears for take off because I love to hear the GE90s rev up.