(FORTUNE Magazine) – It's not easy, nor necessarily smart, to go through airport security with a satchel of noise-canceling headphones. Even after I explained that I was testing six pairs to see which ones most effectively shut out the drone of jet engines, the security guard still made me take off my boots.

Noise-canceling headphones make it possible to listen to music, DVD soundtracks, or in-flight entertainment systems without cranking up the volume to ear-damaging levels. Or they can simply reduce the ambient-noise levels, while at the same time permitting the user to hear important announcements from the flight crew, like "Would you care for something to drink?"

Unlike ordinary headphones, the noise-canceling kind typically contains a microphone and a digital processor that continuously analyze ambient noise and issue an opposite sound wave. You'll recall from physics class that opposite waves cancel one another. Flipping a switch activates the noise-canceling system, and the roar of the engines is neutralized into something that sounds more like a gently babbling brook.You'll hear more sonic detail without having to crank up the volume.

So, listen up. Here are the results:

The overall best performer was the Bose QuietComfort headset ($299). The speakers reside in cups that completely cover the ear and passively block outside noise; coupled with the active noise cancellation, the setup delivers the best performance of any of the headphones I tried. The drawback, besides price, is bulk. These monsters come with their own padded-leather travel bag, complete with a shoulder strap! On the positive side, they are so geeky and intimidating that all you have to do is put them on, and jabbering seatmates will leave you alone.

Equal to the Bose in sound quality but at opposite ends of the scale in design and bulk are the Etymotic ER4P canal phones ($330). The tiny speakers fit entirely into the ear. After an unfortunate Q-Tip incident, my doctor warned me never to put anything smaller than my elbow into my ear canals, so it was with some trepidation that I tried the ER4Ps, which burrow halfway to the brain. The speakers are covered with soft (and, fortunately, washable) rubber flanges and optional polyfoam inserts. With the proper fit (Etymotic suggests moistening the flanges for best results--ick!), the results are impressive. Sound quality is very good, if a bit bright. However, the cord is microphonic, meaning it picks up and transmits noise as it drags across your shirt, and the ear inserts can become uncomfortable during long flights.

Although they didn't attenuate the cabin noise nearly as well as the Bose or Etymotic systems, the Sennheiser HDC 451 headphones with active NoiseGard Mobile technology ($150) offered a great balance of sound quality and comfort. If you can't abide spending $300-plus for the Bose or Etymotic models, the Sennheisers are the best alternative.

For a compact, folding headset, my choice would be the NoiseBuster Extreme ($39), which offered decent but not Bose-level performance.

One way to overcome aircraft cabin noise is to make your music louder, and the Boostaroo amplifier ($20) obliges. Even better, it allows up to three people to share the stereo output from a single device, assuming they all have headphones. If you have two or three kids on a long car trip, you need this gizmo.