Aviation Security Measures and Domestic Terrorism Threats

January 15, 2021

Aviation Security Measures and Domestic Terrorism Threats

After the January 6, 2021, security breach of the United

States Capitol, some Members of Congress have advocated

restricting the air travel of individuals who may seek to

incite or carry out further violence. The Federal Bureau of

Investigation (FBI) is reportedly considering placing

individuals who illegally entered the Capitol on the

Transportation Security Administration (TSA) No-Fly List.

This In Focus discusses the circumstances under which air

carriers, TSA, and other federal authorities may restrict

domestic airline travel in response to security threats.

The No-Fly List and Airline Passenger Prescreening

The No-Fly List is one of several lists maintained by TSA

to identify passengers based on their risk to aviation safety

and national security (See 49 U.S.C. §44903). As the name

implies, individuals on the No-Fly List are to be denied

boarding and referred to law enforcement authorities when

they arrive at an airport to check in for a commercial airline

flight. In addition to the No-Fly List, TSA maintains lists of

individuals who are to receive special scrutiny during preflight security screening and whose carry-on bags and

checked baggage are to be examined more thoroughly. The

primary list of such individuals is referred to as the Selectee

List or Automatic Selectee List to indicate that these

individuals are to be automatically selected for enhanced

screening. Enhanced screening may include measures such

as pat-downs and chemical trade detection swabs to test for

explosives residue. Passengers not on these lists may be

randomly selected for enhanced screening, and passengers

or baggage that trigger alarms during initial screening may

also undergo these additional measures.

Both the No-Fly and Selectee lists are subsets of the

broader consolidated terrorist watchlist, formally known as

the Terrorist Screening Database or TSDB. The TSDB is

maintained by the FBI’s Terrorist Screening Center, which

is responsible for consolidating and disseminating terrorism

data to federal, state, and local law enforcement, and

international partners. TSA’s Secure Flight system checks

passenger names against these lists multiple times between

ticket purchase and the flight’s departure, as the lists are

routinely updated. TSA may expand these Secure Flight

checks to include the larger number of identities in the

complete TSDB when warranted by security conditions.

This can be done when specific threat intelligence suggests,

for example, heightened security concerns regarding a

specific flight, flights along a specific route, flights from a

certain region, or flights to a specific destination. TSA

sometimes refers to this broader use of the complete TSDB

as the Expanded Selectee List, suggesting that, under such

heightened security conditions, additional individuals may

be selected for enhanced security screening. However, the

No-Fly list might not be expanded unless specific

information warrants inclusion of additional individuals on

that list.

In addition to the Selectee list, TSA relies on sets of rules to

temporarily assign certain passengers to two other lists it

maintains, the Silent Partner and Quiet Skies lists.

Individuals may be placed on these lists based on their

recent international travel patterns, and are subject to

enhanced screening measures, including additional baggage

screening, for a period of time.

Historically, the TSA lists and the broader TSDB have

focused mainly on international terrorist threats. The FBI

most recently released data about its security lists in

September 2011. At that time, about 98% of the roughly

420,000 identities contained in the TSDB referred to

persons who were not U.S citizens or legal U.S. residents.

The No-Fly list then consisted of about 16,000 identities, of

which fewer than 500 referred to U.S. persons. The Selectee

list was said to also contain about 16,000 identities,

although the FBI did not specify how many of those were

U.S. persons. The TSDB apparently has grown

considerably since then. According to press reports, about

1.2 million people were on the watchlist in 2017, including

about 4,600 American citizens. Official updates regarding

the size and scope of the No-Fly and Selectee lists,

however, have not been made public.

TSA was required to establish a procedural mechanism

enabling people to challenge their inclusion on the No-Fly

list or other lists that effectively barred them from traveling

by air. The Department of Homeland Security’s Traveler

Redress Inquiry Program (TRIP) maintains a website

through which individuals who claim to have been

misidentified may seek redress, but such individuals may be

barred from air travel or subject to enhanced screening until

their cases are adjudicated.

Airline Blacklists

Airlines’ contracts of carriage, to which passengers agree

when they purchase tickets, oblige passengers to obey

airline rules and policies and comply with crewmembers

performing their duties. Airlines may refuse to provide

service to individuals who refuse to wear masks or facial

coverings for the duration of the flight, as airlines have

uniformly required in response to federal recommendations

to limit the spread of COVID-19. Airlines may also remove

disruptive or uncooperative individuals from an airplane,

and may ban them from future flights. Airlines are not

obligated to notify the Federal Aviation Administration

(FAA), TSA, other federal agencies, or other airlines of

individuals who have been banned from future flights. If

incidents are brought to their attention, however, FAA or

TSA may investigate to determine whether individuals may

have violated federal aviation safety or security regulations.

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Aviation Security Measures and Domestic Terrorism Threats

Enforcement of Federal Aviation Regulations

Airlines may notify FAA of passengers who are disruptive,

disobey instructions from airline crewmembers , or interfere

with airline crew. If FAA determines that an individual

violated 14 C.F.R. §121.580, which prohibits anyone from

assaulting, threatening, intimidating, or interfering with a

crewmember performing their duties , it may impose civil

penalties and, in certain cases may refer cases to the

Department of Justice to assess whether federal criminal

statutes may have been violated.

Federal Jurisdiction of Crimes Committed

Aboard Aircraft

In addition to FAA and TSA, federal law enforcement

authorities have jurisdiction over criminal acts that occur on

board aircraft. From the time the external doors of an

aircraft are closed in preparation for flight until they are reopened, any domestic flight, a U.S.-bound flight, or a U.S.registered aircraft operating anywhere in the world is said

to be within the “special aircraft jurisdiction of the United

States” (see 49 U.S.C. Chapter 465). Alleged federal crimes

occurring in that jurisdiction are investigated by federal law

enforcement and prosecuted by the Department of Justice.

These include air piracy, interference with air crew,

destruction of aircraft or aircraft facilities, carrying a

weapon or explosive device, and a host of serious crimes

incorporated by reference including assaults; maiming;

murder; manslaughter; attempted murder or manslaughter;

theft or attempted theft by force, violence, or deception; and

sexual abuse.

Federal statutes require TSA to deploy Federal Air Marshal

Service teams on all flights assessed to pose a high security

risk based on threat and vulnerability assessments. Air

marshal duties are focused on detecting and preventing

terrorist attacks against an aircraft in flight, but in some

instances they may respond to violent criminal behavior

onboard an aircraft. Sworn federal, state, and local law

enforcement offers that receive training and TSA approval

may also carry firearms on board commercial flights under

limited circumstances and could assist in responding to

criminal conduct. Additionally, under the Federal Flight

Deck Officers program, TSA deputizes airline pilots who

volunteer to travel armed to protect the flight deck from

terrorist attacks. However, armed pilots would not typically

intervene in incidents inside the aircraft cabin, but would

instead focus on diverting to an airport where law

enforcement resources on the ground could respond.

Charter and General Aviation Flight Security

Actions to restrict the travel of certain individuals aboard

scheduled airline flights may result in those individuals

instead seeking to travel on charter aircraft. Domestic

charter flights are not routinely screened against the TSA

lists, and only passengers and their baggage traveling on

charters aircraft weighing more than roughly 100,000

pounds (somewhat larger than a typical Boeing 737) are

required to undergo physical screening. For smaller jets,

passengers are not routinely screened, but flight crew must

undergo security background checks. However, all charter

and private general aviation flights inbound to Washington

Reagan National Airport, regardless of size, are subject to

more extensive security measures, including screening of

all passengers and a requirement for TSA-approved armed

security personnel on board all flights.

The airspace surrounding Washington, DC is off limits to

private aircraft, with certain exceptions. Flights operating in

a 30-mile outer ring beyond the Flight Restricted Zone

above Washington, DC, a circle with a 15-nautical-mile

radius extending from the surface to 18,000 feet, must file a

flight plan and maintain constant radio communication with

air traffic controllers. Such flights are closely monitored.

Defensive measures have been put in place to intercept and

interdict unauthorized non-commercial aircraft that stray

into the restricted zone.

Potential Limitations and Concerns

While the No-Fly List might prevent some individuals

intent on carrying out violence from traveling on a

commercial airline flight, it would generally not restrict

travel by other modes. Identities contained within the

TSDB, however, could be shared with law enforcement on

an as-needed basis to restrict access to certain facilities and

events.

The various TSA lists may be of limited usefulness outside

of the aviation security context. They would not, for

example, be capable of stopping individuals from lawfully

transporting firearms to sites where armed protests are

planned. In general, airline passengers, including

individuals that may be on the TSA Selectee or Enhanced

Selectee lists, are not prohibited from transporting firearms

aboard aircraft so long as the firearms are transported

unloaded and locked as checked baggage. On January 17,

2017, a mass shooting in a baggage claim area of the Fort

Lauderdale-Hollywood International Airport in Florida was

perpetrated by an arriving passenger who had properly

declared the handgun and two magazines used in the attack

and had transported them in a locked box as required by

federal regulations. In mid-January 2021, some airlines

temporarily prohibited passengers from checking firearms

on flights to the Washington, DC area. Somewhat relatedly,

proposals to impose a waiting period on the purchase of

firearms by individuals on the No-Fly List or whose

identities are included in the broader TSDB have been

introduced in recent Congresses, but have not been enacted.

Significantly expanding the No-Fly List could increase the

number of misidentifications, potentially resulting in

delayed or denied boarding of more passengers. Further

complicating matters is that some individuals who might be

targeted for inclusion on the No-Fly or Selectee lists based

on suspected participation in the January 6, 2021, breach of

the U.S. Capitol or other domestic incidents may have been

previously cleared to participate in trusted traveler

programs, such as TSA’s PreCheck or Customs and Border

Protection’s Global Entry. Individuals who participate in

these programs are eligible for expedited screening at TSA

airport checkpoints. While placement on the No-Fly or

Selectee lists would presumably terminate an individual’s

participation in these programs, it may raise questions

regarding the effectiveness of threat assessments conducted

under these programs.

Bart Elias, Specialist in Aviation Policy

https://crsreports.congress.gov

IF11731

Aviation Security Measures and Domestic Terrorism Threats

Disclaimer

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