I also travel a lot. I've tried a few things. Shure E3's sound great and cost $179. I also have a pair of Sennheiser HD580's. They sound terrific, but they are "open" which means they are worthless on a plane because they let too much noise in. Also, don't know what your sleeping situation is, but the open headphones also let a lot of sound out, which means if someone is trying to sleep in the bed next to you -- you will bother them. So, though I love the open Sennheisers, I hardly ever get to use them. I also bought a pair of Sennheiser 280 PRO's, which are closed headphones. I have a buddy who bought the Bose "noise cancelling" headphones and we took a flight together.
IMO, the Sennheiser 280 Pro's sounded better than the Bose and the Sennheisers only cost $100 compared to the $300 he paid for the Bose. "Noise cancelling" means the hedphones have microphones in them. They pick up the ambient noise and then the headphones put out a tone that "cancels" the ambient noise. It does work -- the ambient noise disappears, but the noise the headphones put into your ears means you are getting noise mixed with your music. With the Sennheiser 280 Pro's, they are closed, so that blocks out some of the ambient noise and then when you play music, you cannot hear anything outside. If you get the Sennheisers, play music through them for about 40 hours before using them -- they really improve and then sound good. I haven't tried the Shure E3's on a plane yet, but they sound a little better than the Sennheiser 280 Pro's, so I would bet they will sound better than the Bose Noise cancelling headphones as well -- and cost more -- and when I have them in my ears, I cannot hear anything outside, so based on that, I would bet they will also sound great on a plane. If you need something for travel and to keep from bothering those around you, the Sennheiser 280 Pro's are a great bang for the buck. One other issue -- you've got to decide whether you like having earphones "in" your ears or headphones "on" your ears.
