Private aviation terms, in plain English

The short forms and jargon you will meet on this site and on a flight plan, with what they mean for you.

PPR Prior Permission Required: You must ask the airport and be given permission before you land or take off. Ring or email the airport, or ask your operator to. A filed flight plan does not count as permission.
Slot: A time window agreed with the airport, or with air traffic control, for arriving or leaving. Busy airports such as Northolt book slots well ahead.
CTOT Calculated Take-Off Time: A departure time given by air traffic flow management (Eurocontrol in Europe) when the route ahead is busy. The aircraft has to take off inside the window, which runs from five minutes before to ten minutes after the CTOT.
ATFM Air Traffic Flow Management: The system that spaces flights out when the airspace or an airport is full. It is where a CTOT comes from.
FBO Fixed Base Operator: A private aviation terminal and the company that runs it. It looks after passengers and crew, fuels and parks the aircraft, and arranges cars, catering and customs on the day.
Handling agent: The company that deals with the aircraft and passengers on the ground. At some airports handling is compulsory, so you have to use the airport's own or an approved one.
GA General Aviation: Flying that is not scheduled airline service. It covers private and business jets, light aircraft and helicopters.
Business aviation: The part of general aviation that uses aircraft for business and private travel, usually jets and turboprops.
AOC Air Operator's Certificate: The approval an operator holds from its aviation authority to fly passengers for payment. When you charter, this is the company that actually flies you.
Operator: The company that owns or manages the aircraft and employs the crew.
Broker: A middleman who finds an aircraft and an operator for a passenger, and arranges the charter between them.
Charter: Hiring a whole aircraft for your own trip, as opposed to buying a seat on a scheduled flight.
Positioning flight: A flight with no passengers, to move an aircraft to where it is needed. Also called an empty leg or ferry flight.
ICAO code: The four-letter code for an airport, such as EGLF for Farnborough. Pilots and air traffic control use it. The first letters show the country or region.
IATA code: The three-letter code for an airport, such as FAB. You see it on airline tickets and baggage tags. Many small airfields do not have one.
ARP Airport Reference Point: The single point used to say where an airport is. The maps in this guide centre on it. It is not the terminal door.
Apron: The paved area where aircraft park, load and refuel.
Stand: A marked parking place for one aircraft on the apron.
Taxiway: The paved route aircraft use to get between the runway and the apron.
Runway designator: The number painted on the runway. 03/21 means the two ends face roughly 030 and 210 degrees. L, C and R separate parallel runways.
Heliport: An airfield for helicopters only. A helipad is a single landing pad, often on a roof or in the grounds of a hotel or estate.
Altiport: A mountain airstrip with a sloping runway, such as Courchevel.
Customs: The check on goods you bring in. At many small airports customs is by arrangement, so it has to be booked before you arrive.
Immigration: The passport check when you arrive from another country. It follows the same rules as at any other airport.
GAR General Aviation Report: A form UK private flights send in advance when they cross the border, with the aircraft, crew and passenger details.
GenDec General Declaration: The standard form listing the aircraft, crew and passengers on an international flight.
Schengen: The group of European countries with no routine passport checks between them. Flights between Schengen and non-Schengen countries are treated as international, with checks.
Curfew: Hours when an airport restricts or bans flights, usually to limit noise at night.
Noise abatement: Local rules on how and when aircraft may fly near an airport to reduce noise on the ground.
H24: Open 24 hours a day.
SR-SS Sunrise to sunset: Hours given as sunrise to sunset, often at small airfields with no runway lights.
O/R On request: Open if you ask in advance.
AIP Aeronautical Information Publication: Each country's official book of rules and airport details. It is the source for the facts on these pages.
NOTAM Notice to Air Missions: A short notice of something that affects flying, such as a closed runway or a temporary restriction.
METAR: A coded weather report for an airport, usually issued every half hour.
TAF Terminal Aerodrome Forecast: A coded weather forecast for an airport, covering the next day or so.
QNH: The air pressure setting pilots use to read the correct height above sea level.
CAVOK Ceiling and Visibility OK: Good visibility, no significant cloud and no bad weather.
VFR Visual Flight Rules: Flying by sight. It needs good enough weather to see the ground and other aircraft.
IFR Instrument Flight Rules: Flying by instruments, which allows flights in poor visibility and cloud.
ILS Instrument Landing System: Radio guidance that lines an aircraft up with the runway in poor visibility.
Crosswind: Wind blowing across the runway rather than along it. Every aircraft has a limit.
Kt Knot: One nautical mile an hour, a little over 1.15 mph. Wind and aircraft speed are given in knots.
nm Nautical mile: 1,852 metres, about 1.15 statute miles. Flight distances use it.
UTC Coordinated Universal Time: The time standard used in aviation. Weather reports and flight plans use it. It matches UK winter time and is an hour behind UK summer time.
ETA Estimated Time of Arrival: When the aircraft expects to land.
ETD Estimated Time of Departure: When the aircraft expects to take off.
MTOW Maximum Take-Off Weight: The heaviest the aircraft is allowed to be at take-off. It sets which runways it can use.
GPU Ground Power Unit: A trolley or vehicle that powers the aircraft while its engines are off.
De-icing: Spraying the aircraft to remove ice and frost before departure.
Turboprop: An aircraft with propellers driven by jet engines. It uses shorter runways and suits short hops.
Light jet: The smallest business jets, usually four to seven passengers.
Midsize jet: A mid-range business jet, usually seven to nine passengers.
Large jet: A long-range business jet with a bigger cabin, usually ten or more passengers.
Still-air time: The flight time with no wind. The times on this site are still-air estimates, so a headwind or tailwind will change them.