The 747,777, and the 767U/T/Z all take the twin plug for n/c headphones. They are both the same size. Sometimes in the bulk headset bag that the F/A's use to distribute the onboard noise canceling headsets, there may be some adapters. I have found them more on the 747 than any of the other planes. I'm talking on the a/c with flatbed seats. There are just a couple of 767's that have not been converted, but the other big jets 747,777,A330 and 767/U/T/Z all have the large twin plug. I use one of the airplane adapters with my Bose QC 's on my I-Pad. I fly on these planes for a living, so I know what I'm talking about. However, the adapters that come with those cheap ear buds that they give away and sell on domestic flights are garbage. If I were you, I'd do what the previous poster says, stop by a Bose store and get a new one.