I bought Audio Technica ATH-M50s a few months ago off of Amazon. Having worn them for a few flights, I've been extremely impressed with noise isolation. While they don't have active noise cancellation, I cannot hear any outside noise, whether loud or soft, with these headphones on. After about 40 hours of usage, they sound even better than they did out of the box.

http://www.amazon.com/Audio-Technica.../dp/B000ULAP4U