Airport Security Searches are Generally Permitted Without a Search Warrant
Most Americans recognize that when they go to the airport to travel on public air transportation they have a diminished expectation of privacy in their luggage, clothing, and persons (otherwise unexposed body parts)—and that some lesser degree of privacy is necessary to keep passengers, crew, civilians, and infrastructure (buildings, houses, roads, stadiums, etc.) safe from bombs, threats, attacks, hijackings/skyjackings, and other acts of terrorism.
Airport security searches—including electronic scans of persons, luggage, and other property, as well as physical searches of luggage and pat downs of persons—are generally searches within the meaning of the Fourth Amendment to the U.S. Constitution. If these searches are made without a search warrant they must fit with an exception to the Fourth Amendment’s warrant requirement.
Most courts view airport security screening and other airport security searches as an administrative search—performed by the Transportation Security Administration (TSA) (an administrative agency). The U.S. Supreme Court has held that if a government interest exists beyond the normal need for law enforcement, an administrative authority may perform a reasonable search to satisfy the government’s interest.
Thus, courts have generally allowed limited searches by administrative agencies under the theory that persons who engage in activity (flying) that is regulated by administrative agencies consent to such searches.
If a search is an administrative search, the courts may balance the individual's privacy expectations against the government's interests to determine if it is practical to require a warrant or some level of individualized suspicion in the particular context (airport security screening).
The Aviation Transportation and Security Act—a federal statute located in the United States Code, beginning at 49 U.S.C. §114—provides much of the authority relied on by the Department of Homeland Security (DHS) and the TSA to perform airport security searches without violating the Fourth Amendment.
Dog Sniff Searches
The police and other law enforcement (airport security, border patrol) use trained dogs with extraordinary scent detection capabilities to identify illegal narcotics and explosives in motor vehicles and luggage, for example. Whether a dog sniff inspection of such things or places constitutes a search or seizure under the Fourth Amendment to the United States Constitution depends on whether the owner of the personal or real property has a reasonable expectation of privacy that is invaded by the inspection.
The U.S. Supreme Court has held that a dog sniff inspection in public places—such as the exterior of a motor vehicle stopped for a traffic violation or luggage at the airport—does not implicate legitimate privacy interests in the interior of the motor vehicle compartment (trunk, etc.) or luggage. See Illinois v. Caballes, 543 U.S. 405, 409 (2005); United States v. Place, 462 U.S. 696, 707 (1983).
This is because a person does not have the same reasonable expectation of privacy in public places such as a roadway or airport—in which a person must reasonably expect some government intrusion—as in their home, in which a person has a more complete reasonable expectation of privacy. For this reason, a warrantless dog sniff of the exterior of a person’s home would generally violate a person’s reasonable expectation of privacy under the Fourth Amendment.
In permitting warrantless dog sniff searches of the exterior of a motor vehicle and of luggage at the airport, the Supreme Court reasoned that although a person possesses a Fourth Amendment privacy interest in the contents of a motor vehicle trunk or personal luggage, a canine sniff by a well-trained narcotics detection dog does not require opening the luggage. Such a dog sniff inspection does not expose noncontraband items that would otherwise remain hidden from public view—a stark contrast to an officer's rummaging through the contents of the motor vehicle trunk or luggage.
Thus, the manner in which information is obtained through a dog sniff inspection is much less intrusive than a typical search, as the dog sniff discloses only the presence or absence of narcotics, explosives, or other contraband items. Thus, despite the fact that the dog sniff tells the authorities something about the contents of the luggage, the information obtained is limited, and this limited disclosure also ensures that the owner of the property is not subjected to the embarrassment and inconvenience of more intrusive investigations and searches.
In Texas, as in the rest of the United States, airport security searches are generally permitted without a search warrant due to the administrative search exception to the Fourth Amendment. The Transportation Security Administration (TSA), under the Aviation Transportation and Security Act (49 U.S.C. §114), conducts these searches to ensure the safety of passengers and infrastructure from potential threats. The courts have recognized that individuals have a diminished expectation of privacy at airports and consent to searches by participating in air travel, which is regulated by the TSA. Dog sniff searches by law enforcement at airports are also considered constitutional, as they do not implicate legitimate privacy interests and are limited in scope, revealing only the presence or absence of narcotics, explosives, or other contraband without exposing noncontraband items. The U.S. Supreme Court has ruled that such inspections in public places like airports do not violate the Fourth Amendment, distinguishing them from more intrusive searches that would require a warrant.
