The 'inflight adapter' is just a little attachment that you'd plug into the end of the headset's audio cord which would fit into the jack in the armrest of some aircraft. I've found most airplanes no longer use this type of jack anymore and also most people would use the 'bluetooth' section of the headphones to connect wirelessly with an mp3 device anyway. It's nice though that the adapter is included, just in case you found yourself in a situation where you'd use it.