I just flew to Vegas a few weeks back and lithium batteries are not aloud to be in checked luggage they must stay in carry on in pressurized cabin . with the 20 times they announced it before boarding I sat there thinking about the newer detectors so many use that have built in rechargeable batteries and if they are easily removable or do the hard cases I've seen with what I believe is a pressure valve of some kind would do the trick . of course by the time I boarded the plane I made up my mind I'll only detect where I can drive to in my van which 49 out 50 US states is possible . Of course with my garret AT Max battery removal is simple and the garrett carrot to be in a hard case but my headphones would need to be with me in pressurized cabin along with all batteries for other 2 . For me personally way to much extra bs and stress to travel by plane to detect somewhere ....