Pros: work like similar priced ($20-$30) in-ear earbuds
Cons: not "active" noise-canceling; small control box adds bulk
The bottom line: They are better (but not much) for a plane ride than regular in-ear earbuds at the same price.
"Active noise canceling" means that the circuitry should actively listen for noise and generate sound waves to cancel out (usually low frequency hum) noise.

There is no microphone which listens for noise and no circuity to cancel unwanted noise, despite the box saying, "sophisticated electronics to reduce unwanted external noise - significantly enhancing your listening experience". These actually do produce some "canceling sound" when turned on, but only a small fraction of what my Bose headphones produce, not enough to even notice on a plane.

Essentially these are earbuds with an amplifier that can boost the volume 20% or so higher. With louder music, I have to turn my MP3 player down 10% (from full blast) to prevent distortion, so I could potentially get 10% more volume out of this unit (at full blast) than regular earbuds.

Just being an in-ear set (much like a set of earplugs), outside noise is however reduced a lot (I'd say 70%), just like a set of earplugs do. With the box turned off, the sound quality is on par with $20-$30 in-ear earbuds. With the box turned on (essentially a booster amplifier as described above), very light distortion is introduced (barely and unlikely noticeable on a plane).

Philips should not claim these are "active" noise canceling.