When it comes to headphones that can block airplane engine drones and other ambient noise, you generally have two choices. Active noise canceling headphones sample outside noise with microphones and add the inverse of that sound wave to your music signal, require batteries, and are typically in the large, over-the-ear type form factor (think Bose QuietComfort line). The other kind, sometimes called sound isolating headphones, use a rubber or foam seal to block outside sound without using power, and are designed to be inserted in your ears rather than surrounding them.
According to MusicGizmos, the Nippon Victor Corporation of Japan has announced the first headphones I've heard about that use both active noise cancellation and in-ear sound isolation: the HP-NCX77. I can't find these listed anywhere else, but that site describes them as costing $65, and from the images, it looks like they have an external module for batteries and noise cancellation circuitry, so you'd have to carry that around as well.
The specs are impressive: the headphones arerated for 70 hours on a charge (or a new battery); the active noisecancelation can remove 20% of outside sound sources from the signal;
frequency response is 8 Hz to 24 kHz; and three different sizes will beavailable to accommodate different ear sizes.
(images from MusicGizmos)
