Yes, aircraft tail numbers (technically known as registration marks) are a matter of public record. In the United States, the Federal Aviation Administration (FAA) maintains the Civil Aviation Registry, which allows anyone to look up a tail number (starting with "N") to find the aircraft's make, model, year of manufacture, and the name and address of the registered owner. Most other countries have similar registries maintained by their national aviation authorities, such as the Civil Aviation Authority (CAA) in the UK or Transport Canada. This transparency is a cornerstone of aviation safety and accountability, allowing for the tracking of maintenance records and ownership history. However, some owners—particularly celebrities or large corporations—use "shell companies" or trusts to register their planes to maintain a degree of privacy regarding their personal identity. Despite this, the tail number itself remains visible on the aircraft and can be tracked in real-time by flight-tracking websites like FlightAware or FlightRadar24, unless the owner has opted into specific privacy programs like the FAA’s "Limiting Aircraft Data Displayed" (LADD) program.