As discussed in a  feature article today by Clara-Sophia Daly on Mission Local, recent searches and arrests of passengers trying to board domestic flights at San Francisco International Airport (SFO) have prompted us to question what the airport has done, and what more it could and should do, to comply with city ordinances regulating use of surveillance technology and restricting collaboration with immigration enforcement.

The arrest of Iryna Gorb by ICE at SFO on July 22nd and the search of Nikolas De Bremaeker by the TSA (and/or by Covenant Aviation Security, the contractor that supplies most of the checkpoint staff at SFO) at SFO on June 10th, raise questions about (1) the technologies in use to flag passengers to components of the Department of Homeland Security (DHS) based on airline reservations, (2) whether equipment owned or operated by the airport is used to collect data passed on the DHS, (3) what if any limits are placed on warrantless access by DHS agents to airport premises, and (4) whether the policies of the airport, as put in place by the SF Airport Commission as an agency of the City and County, comply with city ordinances.

For both domestic and international flights, the DHS requires airlines to send information about all passengers and their itineraries to DHS components starting 72 hours before departure.  Reservation and itinerary information for international flights is sent to US Customs and Border Protection (CBP) and included in its Automated Targeting System (ATS). Information for domestic flights is sent to the Transportation Security Administration (TSA) through its Secure Flight system.

No airline is allowed to issue a boarding pass for either a domestic or international flight unless and until it receives an individualized, per-passenger, per-flight permission message from the TSA or CBP in the form of a “boarding pass printing result” (BPPR). The default in the absence of a favorable BPPR is not to allow them to fly. These fly/no-fly decisions are based on a black box of secret algorithms that incorporate list-based rules (blocklists) and other rules based on other known and unknown data.

What’s less well known is that the DHS doesn’t just use the information it gets from airlines to decide whether or not to allow you to fly. It can also use this information to generate “handling codes” instructing checkpoint staff to conduct special searches of your person and property, or to generate messages to other agencies that may want to arrange an “unwelcoming” party to intercept you at the airport, on departure or on arrival, to question, search, or arrest you – with or without a warrant.

We question the legality of many of these activities. Many of them have not yet been reviewed or approved by any court, and have little or no basis in law.

Airline passengers need to know that, legal or not, this is happening.

Travelers also need to know that, as we were the first to report last year (see here and here) and as was later confirmed by the New York Times, some of the most intrusive and legally questionable aspects of these systems of surveillance and control of air travel, based on reservation data from airlines, have in the last year been expanded from international flights to domestic flights. Air travelers should beware.

The Federal government has long claimed broad authority for searches of international airline passengers as part of its authority for border searches. CBP also allows other law enforcement agencies to set a “TECS alert”, even without an arrest warrant or search warrant, so that the agency will be notified whether a person of interest is detected as having a reservation on an international flight. Typically, a TECS alert is triggered when the reservation is sent to CBP by the airline 72 hours before the flight, giving the agency that received the alert time to arrange to intercept the unwary traveler.

These TECS alerts have been used for immigration enforcement as well as to target searches of political activists similar to that of Mr. De Bremaeker. But until 2025, we had never heard of this happening with a domestic flights within the U.S. – only with international flights where it could be rationalized as a “border search”.

A memoranda of understanding (MOU) between the TSA and Immigration and Customs Enforcement (ICE), released this week in response to a Freedom Of Information Act (FOIA) lawsuit, was signed on May 25, 2025. But the MOU fails explian how this TSA-ICE data sharing works or to resolve the legal issues it raises. The MOU was signed in secret, with no notice to airline passengers that information they provide to airlines when they make reservations, buy tickets, or check in for flights may be passed on to ICE, not just the TSA.

The TSA’s legal authority for searches of passengers on domestic flights is limited to “administrative” searches for weapons, explosives, and items that pose a threat to aviation safety. Court have ruled repeatedly that the TSA has no authority to use its checkpoints as a pretext for all-purpose warrantless searches for general law enforcement purposes.

The arrest of Ms. Gorb and the search of Mr. De Bremaeker recently at SFO appear to be further confirmation that the TSA is ignoring the legal limits on its authority and is setting alerts, similar to TECS alerts for international flights, in the algorithms for the Secure Flight system for domestic flights. These allow the TSA to alert other agencies such as ICE to the details of planned domestic air travel by persons of interest and to intercept, question, and/or arrest them — without warrants. This is unconstitutional and should be stopped.

No airline has challenged government demands for access to reservation data. Travelers should demand that airlines that don’t want to collaborate with ICE and other law enforcement agencies in spying on their passengers challenge these demands in court.

As for the airport itself, SFO is located in an unincorporated portion of San Mateo County, but is owned and operated by the City and County of San Francisco. As the landlord at the airport, the city has the same authority to limit access to airport premises that any private landlord has, except for being required (1) not to discriminate between travelers on the basis of protected attributes or acts and (2) to allow space for TSA (or TSA contractors) to inspect passengers and luggage and CBP to inspect international passengers and cargo.

The airport does not have to provide equipment for DHS components. If DHS wants to collect passenger information or operate facial recognition systems, the city can require the DHS to provide its own surveillance equipment, and the city can post its own signs alerting travelers to what DHS is doing.

The city does not have to allow ICE to roam the airport freely, without warrants, outside customs and immigration areas. The city could restrict ICE agents to those areas unless they have warrants.

But we now have more confirmation that reservation data – including data collected at city-owned shared-use check-in kiosks – is being passed on by the TSA to ICE.

These issues have been debated by agencies responsible for  governance of other publicly-owned airports. There were debates in Washington state with respect to airport purchases and installation of shared-use facial recognition systems at Seattle-Tacoma (SEA) airport that fed data to DHS components, and in Minnesota with respect to ICE roaming freely without warrants and abducting people on Minneapolis-St. Paul (MSP) airport premises.

The SF Sanctuary City Ordinance prohibiting assistance to or collaboration with immigration enforcement applies to all City and County agencies — including the airport.  The  SF Surveillance Technology Ordinance exempts “Federally-regulated facilities at the airport”, but not all airport facilities, from some, but not all, of its provisions. Approvals and reporting on surveillance tech are still required, even for activities that aren’t prohibited.

So far as we know, none of the issues posed by access to airport premises, use of surveillance technologies, or sharing of data between airport-owned shared-used systems and DHS components have been assessed by the SF Airport Commission or in terms of the SF Surveillance Technology Ordinance or Sanctuary City Ordinance.

SFO is a City and County agency governed by a commission appointed by the Mayor. The next meeting of the SF Airport Commission is scheduled for Tuesday, August 25, 2026, at 9 a.m. at San Francisco City Hall, Room 400.

We encourage concerned San Franciscans and others who travel through SFO to let the Airport Commissioners know what you think of their collaboration with ICE and allowing ICE agents free rein of the airport. As a gateway to San Francisco, SFO should exemplify our city’s values and message of welcome to all.

The SF Airport Commission should (1) disclose and publicly review its contracts and collaboration with all DHS components, (2) minimize collaboration, data sharing, and access to airport premises by DHS staff, and (3) be prepared to challenge, in court, collaboration or data sharing by the airport or warrantless access to airport premises by DHS agents not mandated by valid, Constitutional Federal laws.