Engine Roar: The loud, continuous noise during takeoff and landing indicates the engines are working hard to get the plane airborne or slowing down on descent.
Ding Sounds: These chimes are signals from the cockpit to the flight attendants, often indicating seatbelt signs, turbulence, or other instructions.
Landing Gear Clunk: A loud clunk or thud during takeoff or landing is the sound of the landing gear retracting or extending.
Brake Squeal: A high-pitched squeal during landing is the sound of the brakes engaging to slow the aircraft down on the runway.
Flap Whirring: A whirring noise before takeoff and landing comes from the mechanical movement of the flaps and slats adjusting on the wings.
Cabin Pressurization Hiss: A hissing noise after takeoff or before landing is the sound of the cabin being pressurized or depressurized.
Turbulence Rattle: The rattling sound during turbulence is caused by the plane moving through varying air pressures and currents.
Hydraulic Pumps: A hum or buzz, often heard during boarding or taxiing, comes from hydraulic systems operating flaps, landing gear, and other control surfaces.