What causes descending aircraft to make a noise like a giant blown bottle? I've lived for years about eight miles NW of Boston's Logan Airport. Although I can't say we get a lot of aircraft noise, once in a while, due to winds or air traffic, there will be a long line of planes traveling right over my house, perhaps 6000-8000 feet up, descending into Logan. At night you can sometimes see three in a row, with a fourth one turning on its landing lights.

Most of the time the overhead planes sound mostly like a roar with some jet whine. However, once in a while a plane will suddenly start making a very strange sound like an enormous blown Coke bottle. Often the pitch will descend during a half dozen seconds, stay constant for a dozen seconds, and then rise again until the sound disappears.

My best guess is that the sound is caused by the pilot lowering the wheels during their descent, and that it only happens on certain models of aircraft. As the wheel well covers open, the air blowing across the wells sounds like that giant Coke bottle, with the pitch decreasing as the opening increases. On certain models, the covers will then close once the wheels are down, causing the pitch to go back up.

(Edit: it's been pointed out that gear isn't dropped until 2000-3000 feet, so in my case that isn't the sound. So, I've removed all those videos, cool though they may be.)

Is my guess right? What model/manufacturer of large jet would make this sound?
Short Answer:

The sound is caused by airflow across holes on the underside of the wings of certain aircraft.

Long Answer:

I too have noted the sound phenomenon that you describe. This video has a great example between 0:26-52 (link starts playback at 0:26 where the noise starts):

                
            

I will readily admit that this answer is mostly just a compilation of what I have learned researching this. Your question intrigued me and I've enjoyed learning about it!

As I discovered as I started researching this, many others are familiar with the noise as well. This article on Airliners.net had a lot of discussion about it, starting with a lot of interesting—but ultimately flawed—theories.

But, that thread led me to the answer to your question, which is: the sound is caused by the "circular opening used to equalise the pressure in wing fuel tanks", according to Euractiv.com

This article on AirportWatch further explains: 


  The Airbus 320 series of aircraft, [...] have been known for many years
  [...] to have a particularly irritating high pitched
  whine. This is caused by air rushing across the under-surface of the
  wing, where there are Fuel Over Pressure Protector (FOPP) cavities.
  This generates noise, in the same way as blowing air over the mouth of
  a bottle. Every A320 series aircraft emits a signature howling noise
  while approaching to land. It is heard most when the plane is
  travelling at around 160 knots, and the frequency is around 500-600Hz,
  which is close to peak sensitivity of the  human ear.


That being said, there is apparently a fix to that problem, as both the aforementioned links describe. As Euractiv.com explains, the fix is a vortex generator:


  a 5-cm triangular piece of aluminium sheet metal upstream of the two
  vents on each wing, in order to divert the air flow and stop the
  whistle. A decade of research went into the vortex generator, which
  stems from efforts to mask a similar whistle produced when air blows
  over the gun ports of warplanes.


This image shows both the FOPP hole, and the VG that softens the sound:

[Image Courtesy of Lufthansa]

Read the articles linked, interesting stuff therein!