One common misconception is that every aircraft must be issued a flight plan before it can fly. Flight plans are not required for flights conducted under visual flight rules (VFR), in which pilots navigate using references on the ground. Most flights take place without one. Just as when you use your car in daily life, pilots can take off and land at the vast majority of airports by using simple, pre-defined procedures, broadcasting their intentions over the radio so that they can coordinate their actions with other pilots in the area, using standardized traffic patterns, and complying with applicable Federal Aviation Regulations.

VFR Flight Plans

A visual flight rules (VFR) flight plan has no air traffic control (ATC) significance. It’s filed with ATC before the flight to facilitate the rescue of pilots and passengers in the very rare instance that the aircraft goes missing. Among other things, the VFR flight plan tells ATC what type of aircraft will be used and what colors it is, how much fuel is on board (expressed in hours and minutes of endurance), how many people are on board, the intended route and altitude of the flight, the anticipated time of departure, and the anticipated time en route (how long the flight will last).

How the VFR Flight Plan is Used

Once airborne, the pilot activates the flight plan by calling air traffic control (ATC) and telling them what time the flight actually took off. This starts a timer in the ATC system. When the pilot lands, he or she contacts ATC to tell them that they have arrived safely at the destination. ATC then "closes" the flight plan.

If the pilot has not arrived and closed his flight plan within 30 minutes of his proposed arrival time, ATC will start calling by telephone to see if the flight has arrived. They may also contact other ATC facilities along the planned route of flight. Information in the VFR flight plan lets ATC know the maximum amount of time the aircraft could have stayed aloft based upon the fuel on board when it departed.

If, after a certain amount of time has passed, no one can locate the pilot or the aircraft, then ATC will launch a search and rescue operation using the Air Force Rescue Coordination Center (AFRCC), which in turn will use the Civil Air Patrol and/or the U.S. Coast Guard Auxiliary to look for the overdue aircraft. Aircraft from the search team will retrace the intended route of flight, looking for the overdue aircraft. Information in the VFR flight plan lets searchers know what kind and color aircraft they are looking for and how many people were on board.

IFR Flight Plans

Instrument flight rules (IFR) flight plans contain the same information as visual flight rules (VFR) flight plans. However, IFR flight plans are used by air traffic control (ATC) to reserve the time and location of use for any airspace needed by the aircraft operating under IFR. The airspace needed by the IFR flight will be used exclusively by that aircraft from the time of takeoff until it has landed. Based upon the intended route of flight, pilots will be issued an IFR "clearance" to operate. In case of radio failure during the IFR flight, pilots will follow the exact route in the IFR clearance, and ATC will anticipate their path, altitudes, and times along the route based upon a combination of the IFR flight plan and the IFR clearance issued by ATC to the pilot. IFR flight plans can also trigger search and rescue operations if needed.