Airlines do not consider travel pillows as a product considered as ‘dangerous goods’ for use in the cabin of an aircraft. FaceCradle is made of memory foam which could act as a protective device when in use.  With regard to the harness, it is only used in 2 of the 5 modes we call Deep Sleep as described on the product packaging.  It is important to note that Deep Sleep Modes are similar to an airline emergency brace position. It is possible that when asked to fasten seat belts for pending turbulence or emergency, an airline flight attendant may ask you to fold down and detach your FaceCradle.