mgm:
You might want to try the Sony NC-10 noise-cancelling "ear-plugs." They are super effective, and I think they both work and sound better than my NC-20 headphones. (Sadly, I have a slightly malformed earlobe on my left ear, so they won't stay in. Violins, please....)
They are very small, and could probably be worn as easily and as comfortably as the foam "roll-your-own" ear plugs that most of us use. Bit pricey at CAD$200, but worth it if you fly a lot. I'm on my third pair of headphones in a year. I lost the first two, ;( and I still go back and drop another 200 bucks to replace them. This time, I put my name on them.
Regards,
Ken Hamer