Are plane tracking services based on Automatic Dependent Surveillance–Broadcast (ADS-B) transmissions that do not honor the Federal Aviation Administration's (FAA) Limited Aircraft Data Display (LADD) program, such as Airplanes.Live or TheAirTraffic, legal to use?
Is it legal to operate a feeder station for one of these?
Is it legal to run one of these services?
Section 566 ("RIGHT TO PRIVACY WHEN USING AIR TRAFFIC CONTROL SYSTEM", page 3385) of the 2018 FAA Reauthorization Act, the law which created LADD, says,
Notwithstanding any other provision of law, the Administrator shall, upon request of a private aircraft owner or operator, block the registration number of the aircraft of the owner or operator from any public dissemination or display, except in data made available to a Government agency, for the noncommercial flights of the owner or operator.
This says nothing about creating legal obligations for anyone except the FAA Administrator, so it seems that LADD is not inherently binding on anyone except the FAA.
However, the FAA's page on LADD says,
Vendors who subscribe to FAA SWIM [System-Wide Information Management] Data feeds are bound by a Data Access User Agreement to filter any LADD participant from public display of aircraft flight data.
Thus, flight trackers using FAA SWIM data are required to comply with LADD, even if they obtain data on the aircraft from another source. This requirement is based on their contract with the FAA, not on federal statutes or regulations.
The wording of the FAA's site also implies that compliance is not mandatory for trackers that do not have agreements with the FAA to use SWIM data.
Other countries may have similar programs that are binding, however.