ckforensic - The Shure E4cs work extremely well on a plane. Even without a NC circuit, they are quieter than the Sony MDR-NC10s and 11s earplugs I've used before. And beware of the cheaper phones including the Sony MDR-NC11. The sound quality is pretty crappy; if you're used to the Shure, those will not work.
BTW, I agree with all others that at the back of a 777 is just slightly noiser than in front. However, the difference is a lot more on a 747.