The LADD Program, the Open ADS-B Signal Any Receiver Can Read, and What Happens When Aviation Safety Data Becomes a Public Surveillance Tool

Any aircraft with a functioning transponder broadcasting within range of a software-defined radio receiver can be tracked by anyone with roughly $30 in hardware and free open-source software. The FAA’s LADD (Limiting Aircraft Data Displayed) program and the newer Privacy ICAO Address (PIA) program address different layers of this problem - and understanding which layer each one actually covers is critical for any operator who thinks enrollment means invisibility.

How ADS-B Became a Public Surveillance Tool

Automatic Dependent Surveillance-Broadcast (ADS-B) is a radio broadcast. Your aircraft’s transponder takes GPS position data and transmits it as an unencrypted signal roughly once per second. Each message carries your ICAO hex code, GPS-derived position, altitude, velocity vector, and squawk code. It radiates outward in all directions on either 978 MHz (for lower-altitude general aviation) or 1090 MHz (the standard transponder frequency). Any receiver within line of sight can read it.

This openness is the design intent, not an oversight. No encryption, no handshake, no access credentials required. The more receivers that can see any given aircraft, the better the traffic picture, the lower the controller workload, and the better the situational awareness for everyone sharing the airspace.

What the engineers and policy architects did not fully anticipate when NextGen was being designed in the 1990s and early 2000s: someone would eventually build a distributed global network of hundreds of thousands of ground-based receivers, aggregate every signal from every aircraft, and display it on a free public website in something close to real time.

That is exactly what FlightAware and FlightRadar24 did.

The Mandate That Accelerated the Problem

The FAA had been pushing ADS-B equipage for years before it became mandatory, with underwhelming voluntary adoption. In 2012, the FAA published its final rule: by January 1, 2020, virtually every aircraft operating in Class A, Class B, and Class C airspace - and in Class E airspace above 10,000 feet - would be required to have ADS-B Out.

The mandate worked as intended. Avionics shops got busy. Garmin, uAvionix, Appareo, and others moved substantial hardware. Equipage rates climbed to where the FAA needed them.

But as more aircraft began transmitting and volunteer receiver networks simultaneously grew, coverage density on the public aggregator platforms increased sharply in the years around 2020. More aircraft transmitting plus more receivers deployed equals dramatically better data quality and dramatically better geographic coverage. By 2021, what had been an enthusiast curiosity had crossed a qualitative threshold into something approaching comprehensive real-time surveillance of civil aviation.

FlightRadar24 now aggregates data from roughly 60,000 ground receiver stations worldwide, most operated by volunteers. FlightAware runs a comparable network. The result is a real-time traffic picture with roughly 15-second latency accessible from any phone.

What These Networks Actually Track

These platforms don’t only capture ADS-B signals. They also use multilateration (MLAT), a time-difference-of-arrival technique. When multiple receivers pick up the same transponder squawk at slightly different times, the system triangulates position geometrically - without any GPS data from the aircraft itself.

MLAT works on any aircraft with a Mode C or Mode S transponder, not just aircraft with ADS-B Out. A Cessna 172 that hasn’t been upgraded to meet the ADS-B mandate can still be tracked and displayed by these networks, as long as it’s squawking and multiple receivers are in range.

The public surveillance layer extends further than the ADS-B mandate requires. Any aircraft with a functioning transponder operating within coverage range of this receiver infrastructure is potentially visible to the world.

The Privacy Crisis That Forced a Policy Response

Around 2021, accelerating through 2022 and 2023, journalists and researchers demonstrated publicly that you could follow the movements of specific individuals through their aircraft registrations. Private jets associated with celebrities, technology executives, and elected officials. With nothing but public ADS-B data, a registration database, and basic automation, anyone could construct a detailed log of someone’s travel patterns - where they went, how often, the timing of their departures and arrivals.

Social media bots emerged that posted automatic updates whenever certain aircraft departed or arrived. No hacking, no proprietary data, no special access. The aircraft was broadcasting. Volunteer receivers were listening. Free websites were displaying.

This forced the FAA, tracking services, and the aviation community to confront the gap between what ADS-B was designed to do and what it was actually being used for.

What the LADD Program Actually Does

The LADD (Limiting Aircraft Data Displayed) program is the FAA’s existing framework for this problem. Here is precisely what it does and does not do - there is genuine confusion in the operator community.

LADD does not hide your aircraft from air traffic control. ATC sees your transponder signal regardless of LADD enrollment.

LADD does not hide your aircraft from other pilots’ ADS-B In traffic displays. Your position still propagates through the Traffic Information Service-Broadcast (TIS-B) network for aircraft in ground radar coverage.

LADD does not remove you from any government system, law enforcement database, or national security infrastructure.

What LADD does is one specific thing: it instructs the FAA not to pass your position data to commercial third-party flight tracking aggregators. Those services receive real-time data feeds from the FAA under commercial data use agreements that include provisions for honoring a suppression list. If your tail number is enrolled in LADD, those sites don’t display your flights.

You remain fully visible to every system that exists for safety. You are removed from the public display layer those commercial services provide.

The Layer LADD Cannot Reach

This is the gap most operators don’t understand. Radio broadcasts are physical. Your transponder transmits on a public frequency. That signal propagates outward until it reaches a receiver or attenuates below the noise floor.

A software-defined radio receiver capable of capturing ADS-B signals costs roughly $30 in hardware. The decoding software is free, open-source, and runs on any laptop. If your aircraft is transmitting within range of anyone running that setup, your position data is readable regardless of your LADD enrollment status.

This is not a hacking scenario. This is the physics of radio.

LADD addresses the centralized, aggregated, publicly accessible display layer. It does not address the fundamental broadcast at the signal level. These are different things, and conflating them gives a false sense of protection to operators who enroll expecting to disappear.

The More Complete Solution: Privacy ICAO Address (PIA)

Your ICAO hex code is a permanent unique identifier assigned to your specific aircraft and directly linked to your registration in the FAA database. When someone sees your ICAO code in a tracking stream, they can query the registration database and find whose airplane it is.

The FAA approved the Privacy ICAO Address (PIA) program in 2021. Under PIA, your transponder broadcasts a temporary, randomly assigned ICAO code instead of your permanent one. The code rotates on a schedule. It’s not cross-referenced to your permanent registration in any public database. Someone receiving your ADS-B signal sees a valid aircraft in the airspace. They cannot trivially connect that signal back to your tail number.

The safety architecture stays intact. The FAA, air traffic controllers, and authorized agencies can resolve PIA codes to real registrations through secured back-end channels. Traffic separation functions normally. What breaks is only the linkage between your broadcast and your publicly identifiable record in the aircraft registry.

PIA is voluntary enrollment for general aviation, activated through your avionics manufacturer or approved service provider. Uptake in the GA community has been slower than the FAA hoped. The primary barrier is not cost or complexity - it is awareness. Most pilots have never heard this program exists.

For Part 121 and Part 135 operators, LADD at the operator level is the more appropriate mechanism, allowing a fleet to be managed as a unit.

Military, Government, and the Gaps in the Public Picture

Military platforms have used non-cooperative transponder postures for decades. Many military aircraft either don’t transmit ADS-B at all, transmit on a delayed and sanitized feed, or use ICAO codes that map to synthetic registrations with no real ownership information in the public registry.

Federal law enforcement aircraft have their own suppression pathways that run separately from the commercial LADD process. This includes fixed-wing surveillance platforms that have operated over American cities during large public events. Much of this activity was documented by journalists and accountability organizations using public ADS-B data before suppression was more systematically applied - documentation that became harder as suppression became more consistent.

The practical effect is that the picture on public aggregators has significant structured gaps. What you see on FlightAware is not all the traffic. The gaps aren’t random noise. They follow the shape of who has requested suppression and what mechanisms were available to them.

Why This Matters in the Cockpit

Your ADS-B In system is one of the best traffic tools ever put in a panel. But it cannot show you aircraft without functioning transponders, aircraft operating in fully non-cooperative modes, or aircraft where the signal is suppressed. That was always a known limitation.

Understanding that LADD enrollments and military exemptions are part of the structure of that incompleteness helps you calibrate how much to rely on the traffic display versus maintaining your own visual scan and instrument cross-check. The traffic picture is excellent. It is not complete. Those are both true simultaneously.

The Drone Parallel Worth Watching

The FAA’s Remote ID requirement for unmanned aircraft systems is essentially mini-ADS-B for drones - position, altitude, velocity, and an operator identifier broadcast as an open signal. The same privacy tension is already emerging in that space.

The FAA’s current Remote ID framework doesn’t include a suppression mechanism comparable to LADD or PIA. That is an active policy discussion in the UAS community, and however it resolves will almost certainly influence how the manned-aircraft side of this evolves.

Where This Heads

The demand for public access to this data is not going away. Courts in multiple countries have been asked whether ADS-B data constitutes personal data under privacy law. That question is genuinely unresolved. European regulators in particular are wrestling with how data protection law applies to a signal that physically cannot be turned off mid-flight without compromising safety.

At the same time, the technology to track aircraft without any reliance on FAA data feeds keeps getting more accessible. Consumer hardware and open-source software can reconstruct significant tracking capability independent of the commercial aggregator infrastructure.

The technically durable solution is PIA - change what the aircraft broadcasts so the signal is less linkable to identity while keeping the safety function intact. Administrative suppression of data that has already been transmitted on a public frequency is a less stable foundation. The policy need is a clearer framework for who qualifies for suppression, what that suppression actually covers at each layer, and what legitimate public-interest carve-outs look like. Right now it’s a patchwork, and the patchwork has real gaps.

Key Takeaways

• ADS-B is an unencrypted radio broadcast by design - the openness is what makes it work for traffic safety, and that same openness enables public flight tracking.
• LADD suppresses your data from FAA commercial data feeds to aggregator websites; it does not remove you from ATC, TIS-B, or any government system, and it cannot suppress the physical radio signal.
• PIA (Privacy ICAO Address), approved in 2021, addresses the problem at the signal level by rotating your ICAO code - it is the more technically complete solution but remains underutilized due to low awareness.
• A $30 SDR receiver and free software can read ADS-B signals directly, independent of any FAA data feed or commercial aggregator.
• Your ADS-B In traffic display has structured gaps from suppression and non-cooperative aircraft - it is an excellent tool, not a complete one, and visual scanning remains essential.