The Privacy ICAO Address, LADD, and the Fight Over Who Can See Your Tail Number Every Time Your ADS-B Squawks

Every aircraft flying with ADS-B Out broadcasts its permanent, government-issued identity in the clear roughly twice per second, and anyone with an inexpensive software-defined radio can receive it. That identity - a 24-bit ICAO address - maps directly to your tail number in a free, public FAA database, turning your position into your name in just two steps. Two FAA programs, the Privacy ICAO Address (PIA) and Limiting Aircraft Data Displayed (LADD), exist to limit this exposure, but each solves only half the problem.

What Your ADS-B Out Actually Broadcasts

Since January 2020, nearly every aircraft operating in controlled U.S. airspace has been required to fly with ADS-B Out. About twice a second, your equipment transmits a small packet of data: your GPS-derived position, your altitude, your velocity, and - critically - your identity.

That identity is the 24-bit ICAO address, named for the International Civil Aviation Organization. Think of it as your aircraft’s electronic serial number. In the United States, the FAA assigns it when you register the aircraft, and it is locked to your tail number in a public, free, online database.

The chain from broadcast to owner is remarkably short. Your box transmits a hex code. A website maps that hex code to your registration number. The registration number maps to a name and address in the FAA registry. Position to identity to you - two hops.

Why ADS-B Was Never Designed for Privacy

This exposure is not a flaw. It is exactly what ADS-B was built to do. The entire premise of cooperative surveillance is that aircraft announce themselves clearly and constantly so that controllers and other pilots always know who is where. The engineers were solving for safety and situational awareness - privacy was never on the whiteboard.

The two frequencies ADS-B uses, 1090 MHz and 978 MHz, are unencrypted by design. There is no password and no scrambling, because a safety broadcast that only some aircraft can decode is a safety broadcast that fails.

For decades this hardly mattered, because the only practical listeners were the FAA and the airlines using expensive ground infrastructure. The receiver was the barrier. Then cheap software-defined radios arrived. Once a hobbyist could buy a USB dongle for the price of a nice dinner, the entire sky became readable by anyone.

Who Is Actually Listening

Networks of volunteers began pointing those receivers skyward and feeding the data into websites that now display live traffic across the planet. Some large commercial platforms will honor requests to hide certain aircraft. Others explicitly will not - one well-known network markets itself precisely on the promise that it filters nothing and hides no one.

This is not theoretical, and it is not limited to celebrities. Every aircraft broadcasting ADS-B Out appears in these feeds: your home base, your routine flights, and the pattern of when your aircraft moves and when it sits. If you own the only aircraft in the family, that movement pattern is a reasonable proxy for when your house is empty.

Why This Matters for Pilots

For the vast majority of general aviation pilots, this is a low-stakes privacy question. No one is staking out a Cessna 172. The people who genuinely lost something when the receiver barrier fell are a narrower group:

Corporate flight departments that don’t want competitors tracking executive travel before a merger
Public figures dealing with stalkers
Law enforcement and certain government aircraft
High-net-worth owners who don’t want strangers online posting their arrival times

Even if you decide you don’t care, the principle scales down to everyone, and it’s worth understanding what leaves your antenna.

How the Privacy ICAO Address (PIA) Program Works

The FAA’s first real answer arrived in 2019 with the Privacy ICAO Address program (PIA). The clever part is the engineering. Because the 24-bit code is what links your broadcast to the registry, PIA lets an eligible operator get an alternate ICAO address that is not the code published against your tail number.

Your aircraft still broadcasts. It still appears on traffic displays. Air traffic control still sees you perfectly, because the FAA knows the mapping on their end. But the public database lookup - that second hop - breaks. The hex code a listener hears no longer resolves to your name.

There were strings attached. You could not self-assign a random code, because two aircraft sharing one identity is a genuine safety problem. The program required a third-party service provider, and initially it worked only on the ground-based network in domestic airspace, not the same way through the 1090 MHz extended squitter path. It was clunky, aimed squarely at business aviation, and did essentially nothing for small aircraft - most owners never heard of it.

How LADD Differs From PIA

There is a companion program on the data side: Limiting Aircraft Data Displayed (LADD), formerly known as the Block Aircraft Registration Request (BARR).

The two work differently. PIA changes what you transmit. LADD is a request to the FAA not to pass your data along through the government’s own subscriber feed to the flight-tracking companies that receive it that way.

You can hear the weakness immediately. LADD only controls the FAA’s official data pipe. It does nothing about someone on a hilltop with a dongle receiving your raw broadcast directly out of the air. You cannot filter a radio wave that has already left your antenna. An aircraft can be fully LADD-blocked in the government feed and still appear live on a network built from independent receivers. The block was real, but it was a fence with one side missing.

What Changed With the 2024 FAA Reauthorization

The pressure from celebrity-jet-tracking accounts pushed this from an insider topic to front-page news, and that produced the next chapter.

In the FAA Reauthorization Act of 2024, Congress directed the FAA to stand up a process by which any private aircraft owner or operator - not just business jets, not just the well-connected - can request that their registration number be withheld from public display, and to do it without a fee.

That is a meaningful shift. For the first time, the default is being questioned at the policy level: the assumption that registering an aircraft makes your identity automatically and permanently public.

Through late 2024 and into 2025, the FAA acted. It opened the ability for private owners to request their information be withheld from the FAA’s public-facing registry inquiry and released data, and it has been expanding and streamlining PIA so more operators can obtain an alternate address without the old hoops.

The Catch: Registry Blocks Don’t Silence Your Transponder

Here is the part the headlines skipped. Withholding your name from the FAA registry does not silence your transponder. Your ADS-B Out is still broadcasting an ICAO address in the clear, twice a second, on an unencrypted frequency, to every receiver in line of sight.

If that address still maps to you through any independent database - or if a network has already cached the mapping - the privacy you were promised on paper can be far thinner in the air. The registry block solves the easy hop, the government one. The broadcast itself is only solved if you also change the code you transmit through something like PIA. Do one without the other and you’ve locked the front door while leaving the radio on.

Even PIA has a ceiling. It works well domestically on the U.S. two-link system but is far less useful the moment you broadcast on the international 1090 MHz path the rest of the world watches, or when you cross a border. Surveillance is global, and a privacy tool that stops at the coastline is a partial tool.

The Deeper Tension: Transparency Versus Privacy

ADS-B’s greatest strength is also its greatest privacy weakness: it is open, unencrypted, and universal on purpose. That openness is why it’s so safe. A student pilot with a portable receiver can see the airliner descending toward the same airport - collision avoidance democratized.

But the same openness means privacy cannot be bolted on afterward the way you’d add a password to a website. You can’t encrypt a safety broadcast without breaking the safety, and you can’t recall a radio wave. Every fix has to work around the physics, not through it. There are only two levers: change the identity you transmit, or change who is allowed to republish it. Neither is complete alone.

There is also real pressure to make this data more available, not less. Researchers, journalists holding the powerful accountable, airport noise-complaint groups, historians, and accident investigators all rely on open flight data. The same tool that exposes a routine flight also let the public watch government and corporate aircraft in ways that arguably serve the public interest.

This isn’t pilots versus surveillance. It’s a genuine values collision - transparency against privacy, safety against anonymity - and both sides have a legitimate case. The engineering only supplies the levers; how far to pull them is an argument still underway.

Key Takeaways

ADS-B Out broadcasts your aircraft’s 24-bit ICAO address in the clear about twice a second on unencrypted 1090 MHz and 978 MHz frequencies, and that code maps to your name via a free public FAA database.
PIA (2019) assigns an alternate ICAO address so the public database lookup no longer resolves to you, while ATC still tracks you normally.
LADD (formerly BARR) only blocks the FAA’s official data feed - it does nothing about independent receivers pulling your signal straight from the air.
The FAA Reauthorization Act of 2024 requires the FAA to let any private owner request their registration be withheld for free, with implementation rolling out through late 2024 and 2025.
A registry block alone doesn’t help if your transponder still broadcasts a traceable code - you very likely need both PIA and LADD, and even then coverage weakens internationally.