We have a lot of customers who travel with their helmets in their luggage, carry on, and checked-in baggage with no issues. You may want to double check with your airline carrier just to make sure. You may take the IFU (instructions for use) that shows what the device is used for. We even have customers who have put their helmets under the seats on a plane.
When travelling, we recommend using the white protective bag that came with your Theradome.