It is unclear what the OP is really looking for?

LH provides noise-cancelling headphones in long-haul first class. These appear to me use a removeable 3-pronged connecter, presumably one for power, and the other two for left and right channels.

One can remove these headphones and use others as long as you have a 2-pronged adapter. Why you would want to do this escapes me? However one cannot use the LH headphones to say plug into a PC to listen to CD's/MP's/audio from DVD's.

So if you plan to enjoy LH's audio/video/8mm only entertainment then leave your headphones at home. If you plan to utilize your PC for some sort of audio entertainment then you should bring your own headphones.