The LADD Program, the FAA's Flight Privacy System, and the ADS-B Exchange Decision That Made Every Squawk Visible

Every ADS-B Out transponder continuously broadcasts your position, altitude, groundspeed, and aircraft identity on 1090 MHz - a public radio frequency receivable by anyone with appropriate hardware. The FAA’s Limiting Aircraft Data Displayed (LADD) program can remove your aircraft from FlightAware and similar commercial services, but it has no mechanism to prevent volunteer networks from receiving and publishing what you legally transmit. If you’re equipped and squawking, treat your position as public information.

What ADS-B Actually Broadcasts - and Why It’s Not Anonymous

ADS-B Out is a continuous broadcast, not a query-response system like older radar transponders. Your transponder transmits a data packet roughly twice per second, every second you’re airborne and often while you’re on the ground. That packet contains your ICAO aircraft address - a unique 24-bit identifier assigned at registration - along with your GPS-derived position, pressure altitude, groundspeed, track, and vertical rate.

The ICAO address is not anonymous. The first bits encode your country of registration, and U.S.-registered aircraft fall within a specific range of values. The FAA Aircraft Registry publicly cross-references N-numbers with ICAO codes. Anyone who receives your ADS-B transmission can resolve it to your N-number, your aircraft make and model, and the name of the registered owner.

How the Old Radar System Was Different

Secondary surveillance radar worked on a fundamentally different architecture. Ground-based radar interrogated your transponder; your transponder replied. The data stayed inside the ATC system. The public had no radar stations, no way to query your transponder, and no access to the data stream. Access was controlled by the infrastructure required to receive it.

ADS-B removed that barrier entirely. You broadcast continuously in every direction at the speed of light. Any receiver on 1090 MHz within line-of-sight range can hear every transmission.

How Software-Defined Radio Made ADS-B Reception Trivial

Around 2012, a USB dongle based on a television tuner chip - costing less than $30 - turned out to cover the ADS-B frequency. Free decoding software was already publicly available. Within a year, tens of thousands of hobbyists had their own receivers pointed at the sky.

Commercial flight tracking services had been building their networks for years before this. FlightAware launched in 2005; Flightradar24 launched around 2006. The cheap receiver revolution turbocharged both. By the time the ADS-B Out mandate took effect on January 1, 2020, coverage was essentially nationwide. At any altitude above a few thousand feet in a populated area, there was near-certain probability your track was being logged in real time, archived, and searchable by N-number.

The OpenSky Network - an academic research project based at the Swiss Federal Institute of Technology in Zurich - maintains one of the largest publicly accessible archives of historical ADS-B data, covering hundreds of millions of flights with no expiration date.

Why ADS-B Was Designed Without Encryption

The engineers who designed ADS-B knew the physics. An encrypted, authenticated architecture - where only credentialed receivers could decode transmissions - was considered and rejected. That architecture exists in military aviation. The civil aviation community chose not to apply it.

The reasoning was both practical and principled. Encryption would have added significant cost and complexity to every transponder, delayed the mandate timeline, and complicated the interoperability the system depends on. More fundamentally: the entire safety case for ADS-B requires aircraft to be visible to each other without restriction.

When a Cessna 172 receives a traffic alert from a nearby ADS-B-equipped airliner, that works because the airliner’s broadcast is receivable without authentication - no subscription, no handshake. The transmitter doesn’t know who’s listening. That’s the feature, not a flaw.

The BARR Program and How It Became LADD

The FAA’s predecessor program, the Block Aircraft Registration Request (BARR), existed since 2003 - predating ADS-B by several years. It was designed for law enforcement aircraft, sensitive government surveillance platforms, and corporate operations with documented security concerns. The FAA would still receive and use the data for ATC purposes but would instruct commercial aggregators not to republish that registration in consumer-facing products.

FlightAware, Flightradar24, and other commercial services cooperated voluntarily. They valued their data relationship with the FAA; the exclusions were rare and the use cases were legitimate.

Over the following decade, the program expanded beyond its original scope. Wealthy private aircraft owners discovered BARR. File a request, get it approved, and your aircraft disappeared from FlightAware’s public map. By 2022, the FAA determined the program had drifted from its purpose and restructured it. BARR became LADD (Limiting Aircraft Data Displayed). Criteria tightened; applicants had to certify a genuine safety or security need.

The structure remained unchanged. The FAA instructs commercial aggregators to filter certain registrations from public displays. It is a voluntary business arrangement with commercial intermediaries - not a technical restriction on who can receive a public radio signal.

ADS-B Exchange: The Network That Refused to Filter

ADS-B Exchange was built on a different philosophy. Its core argument: aircraft operating in public airspace, transmitting on public radio frequencies, are broadcasting data that is physically receivable by anyone with appropriate hardware. The FAA’s LADD program is an agreement with commercial intermediaries to voluntarily filter their displays. It has no legal mechanism to prevent anyone from receiving and republishing public radio transmissions.

ADS-B Exchange built its receiver network on volunteer contributions, aggregated the data, and published without filtering. No LADD blocks honored. If a receiver heard it, the website showed it.

The ElonJet Controversy and What It Exposed

In 2022, a college student named Jack Sweeney brought this gap to public attention. Sweeney was running a Twitter (now X) account called ElonJet, tracking the movements of Elon Musk’s Gulfstream G650 using data from ADS-B Exchange. The aircraft had a LADD block with FlightAware. It had no protection against a volunteer network that had explicitly declined to honor LADD filtering.

The account grew to over 500,000 followers. Similar accounts tracked other high-profile individuals - Taylor Swift’s aircraft, Jeff Bezos, corporate executives, politicians. The operators had believed their LADD blocks protected them. They had not understood the physics.

Musk’s team reportedly offered Sweeney money to stop. Sweeney declined. The account remained active until Sweeney’s platform access was suspended following Musk’s acquisition of Twitter in 2023. The underlying technical vulnerability was never addressed. It cannot be addressed.

TIS-B and Coverage Gaps Worth Knowing

Traffic Information Service Broadcast (TIS-B) is a related component of the ADS-B architecture. TIS-B is how the FAA rebroadcasts non-ADS-B traffic targets to ADS-B In-equipped aircraft. When your cockpit display shows traffic that isn’t itself transmitting ADS-B, that data typically comes from TIS-B: a ground station encodes a radar return in the ADS-B data format and broadcasts it back down to equipped aircraft in the area.

TIS-B coverage has gaps - leave radar coverage, and you leave TIS-B coverage. Volunteer ground receiver networks, whatever their surveillance philosophy, provide coverage extension in those gaps for situational awareness, even though they serve no official ATC function.

Why Encryption Won’t Resolve This

Some proposals call for adding cryptographic authentication to future ADS-B iterations or successor systems, restricting position data to credentialed receivers only. The engineering community pushes back hard.

Collision avoidance has severe latency requirements. A worldwide aircraft authentication infrastructure would be enormous to build and maintain. And fundamentally, the safety case still requires the Cessna 172 to see the airliner without asking permission - instantly, with no handshake.

ACAS X, the next-generation follow-on to TCAS, is being developed by the FAA and international partners with a more flexible architecture than its predecessor. But even ACAS X is not being designed around encrypted position data. The cooperative, public broadcast model is what scales to the density and diversity of aircraft the future airspace will contain.

What This Means for Pilots

Your ADS-B Out transmission is receivable by anyone in range. LADD removes you from FlightAware’s map. It does not prevent a volunteer receiver network from logging your track. If you are equipped and squawking, treat your position information as public.

LADD is a real program for real use cases. Law enforcement, intelligence-sensitive operations, credible and documented security threats - if that describes your operation, the application is on the FAA website. It does what it says, within the commercial services that honor it.

LADD protection is not operational security. If your mission requires genuine position secrecy, ADS-B Out and position secrecy are incompatible. The FAA sees your position. ATC sees it. TCAS-equipped aircraft near you see it. LADD is a consumer-facing filter, not a surveillance blackout.

The architecture was designed this way on purpose. The safety case for cooperative surveillance is strong, and it depends on the openness of the broadcast. Visibility is a safety value. The system defaults to it.

Key Takeaways

ADS-B Out broadcasts your position, altitude, groundspeed, and aircraft identity continuously on 1090 MHz - receivable by anyone within line-of-sight range with a compatible receiver.
Every ADS-B packet contains a 24-bit ICAO address that can be cross-referenced with the public FAA Aircraft Registry, making transmissions traceable to a registered owner.
The FAA’s LADD program filters aircraft data from participating commercial services like FlightAware and Flightradar24, but has no authority over volunteer networks that receive public radio transmissions directly.
ADS-B Exchange, which does not honor LADD filters, became publicly significant in 2022 when it was used to track high-profile private aircraft operators who believed their LADD blocks protected them.
Encrypting ADS-B data would undermine the collision-avoidance architecture that makes the system work - the cooperative, unauthenticated broadcast is a deliberate safety design choice, not an oversight.