I noticed the loud whining sound on a 767 trip. I was on a 767-200 and it did sound quite loud- but i was sitting right next to the wing at the time so that may explain it. I noticed the noise on the 747-400 but not as loud. I think it all depends where you're sitting. I had an awesome seat next to the left wing on the 767-300 on a trip to Sydney. The view was just fantastic as we crossed low over Botany Bay to land. As the flaps were being selected down i could see through the gap striaght down the water below. Sitting next to a wing is cool because that's where all of the action is happening and on a big jet like a 767 it's awesome seeing it all happen so neatly!