I carry a Bluetooth receiver/transmitter (with aptX low latency feature) in case I want to use my Bluetooth headphones on a plane. I don't use it a lot, but I do like the ability to move in & out of my seat without constantly connecting and disconnecting my headphones.

The specific one I carry is no longer for sale on Amazon, but is a similar one. That particular model both transmits and receives Bluetooth signals; you can save a few bucks with an . Make sure the one you buy supports "aptX low latency" to minimize audio/video sync issues.