identification both at luggage check-in and when boarding. Some countries also fingerprint travellers or use retina and iris scanning to help detect potential criminals, although this is predominantly in relation to detection of immigration violations by inbound passengers rather than security checking of outbound passengers. Criticism With regard to the 2015 Germanwings flight 9525 crash incident, a suicide by pilot where the captain was unable to regain access to the flight deck, some have stated that security features added to commercial airliners after 9/11 actually work against the safety of such planes. Lawsuit In 2003, John Gilmore sued United Airlines, Southwest Airlines, and then-U.S. Attorney General John Ashcroft, arguing that requiring passengers to show identification before boarding domestic flights is tantamount to an internal passport, and is unconstitutional. Gilmore lost the case, known as Gilmore v. Gonzales, and an appeal to the U.S. Supreme Court was denied. See also Airport security No-fly list Security repercussions due to the 2006 transatlantic aircraft plot Canadian Air Transport Security Authority Airport racial profiling in the United States Security theater — unnecessary implementation of security measures for display Don't touch my junk — criticism of full-body pat-downs by the TSA References Aviation security Aftermath of the September 11 attacks