Aside from military and government sensitive flights, flight information collected by the FAA is considered public information because taxpayers pay for air traffic controllers, runways, towers, and other resources utilized by both commercial and private pilots.

Generally, commercial flight plans are not public in the sense that they aren't published for general browsing by the average citizen before a flight departs. These documents contain technical data like specific waypoints, fuel loads, and alternate airports that are intended for Air Traffic Control (ATC) and the airline's dispatch office. However, once a flight is active, much of the data becomes "de facto" public through flight tracking services like FlightAware or Flightradar24. These platforms utilize ADS-B (Automatic Dependent Surveillance-Broadcast) signals, which commercial aircraft are required to broadcast. These signals provide real-time information on the plane's position, altitude, and ground speed, allowing anyone with an internet connection to "see" where a flight is going. While you cannot see the pilot's private notes or the exact fuel weight, the actual path flown is highly transparent. For security and privacy reasons, some private or government flights can request to be blocked from public tracking sites, but commercial airline flights are almost always visible to ensure safety and public accountability in the global airspace.