Works great, although not super comfortable after several hours
I used these on recent international flights and they were great at cutting out loud background noise from the jet engines. You don't realize how awful and wearing the airplane noise level is until you put these on. One drawback: they sit right on your ear and hurt after several hours. For sleeping on flights, old-fashioned dirt-cheap ear plugs work best. But I loved these earphone for when I was awake and wanted some quiet or wanted to listen to my iPod. And they cost a lot less than other noise canceling headphones.