the company has 3 DC's in every plane, and you can bring your own no problem. Whether it's TSO'd or not is between you and any feds that may care to ask. The Harmony system is TSO-pending (I think you'll have to mail it in for the individual test/sticker once they get the all-clear from the FAA), so probably not a bad investment if you want something that's easier on the ears than a DC headset, and easier on the skull than an A20....