How Flying Works

What Every Part of a Plane’s Wing and Tail Does

On 12 November 2001, an American Airlines Airbus A300 climbed away from New York’s JFK airport behind a Boeing 747. It flew into the 747’s wake, the swirling air left behind a large aircraft, and the first officer responded with a series of full, alternating rudder inputs. The loads on the tail built up so fast that the whole vertical fin broke away. The aircraft came down in Queens. Everyone on board and five people on the ground were killed.

The National Transportation Safety Board found that the rudder movements were “unnecessary and excessive”, and that the A300’s very light rudder pedals and an airline training programme had both played a part. The lesson changed how pilots everywhere are taught to use the rudder. It’s also the clearest example of a simple truth: every moving surface on an aircraft has one job, and it works best when used only for that job.

Here’s what each of them does.

Three axes, three main controls

An aircraft can rotate three ways. Roll tips one wing up and the other down. Pitch raises or lowers the nose. Yaw swings the nose left or right, like shaking your head. Each has its own control surface, a hinged panel that changes the shape of part of the wing or tail so the air pushes on it differently.

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Ailerons

Hinged on the outer back edge of each wing. One goes up, the other down, so one wing lifts more and the aircraft rolls.

On the wing

Ailerons sit on the back edge near each wingtip and move in opposite directions. When the right aileron goes up and the left goes down, the left wing makes a little more lift and the right a little less, so the aircraft rolls right. Rolling is how an airliner starts a turn: once it’s banked, part of the wing’s lift pulls it sideways round the curve.

Spoilers are the panels on top of the wing. They do three jobs. Raised on one wing only, they spoil some of its lift and help the ailerons roll the aircraft. Raised on both wings in flight, they act as speed brakes, adding drag so the aircraft can slow down or descend faster. And after touchdown, the ground spoilers (also called lift dumpers) flip up automatically. They destroy most of the wing’s lift, so the aircraft’s weight sits on the wheels and the brakes can grip.

Flaps and slats reshape the wing for slow flight. Flaps slide out of the back edge, slats out of the front. Together they let the wing make enough lift at takeoff and landing speeds without stalling. We cover them in depth in What Flaps and Slats Actually Do.

A Boeing 737 wing just after touchdown, with flaps extended and spoiler panels raised — A Boeing 737 wing just after touchdown: flaps out at the back, spoiler panels standing up on top to dump lift. Photo: Wikimedia Commons (author and licence on the file page).

Winglets: the part that doesn’t move

At the wingtip, higher-pressure air from under the wing curls round to the low-pressure top. That leaves a spinning vortex behind each tip, and it costs energy, a type of drag called induced drag. A winglet is an upturned tip that weakens that vortex.

The modern version came from NASA engineer Richard Whitcomb in the 1970s. In 1979 and 1980, NASA flight-tested his winglets on a KC-135, the military tanker version of the Boeing 707 family. The tests showed about a 7 percent better lift-to-drag ratio, a measure of how efficiently a wing makes lift. Airlines now fit winglets of many shapes, from Airbus “sharklets” to the split scimitar tips on many Boeing 737s, to cut fuel burn.

A United Airlines Boeing 737-800 wingtip fitted with a split scimitar winglet — A split scimitar winglet on a United Airlines Boeing 737-800: one fin up, a smaller one down. Photo: Wikimedia Commons (author and licence on the file page).

On the tail

The tail, or empennage, is mostly about stability. The horizontal stabiliser is the small wing at the back. It balances the aircraft so the nose doesn’t pitch up or down on its own. The elevators are hinged on its back edge: pull back on the controls and they tilt up, the tail is pushed down, and the nose rises.

On airliners the whole horizontal stabiliser can also move, slowly, driven by a large screw called a jackscrew. That’s trim: it sets the tail so the aircraft holds its pitch without the pilots holding the controls. How much that one screw matters was shown on 31 January 2000, when Alaska Airlines Flight 261, an MD-83, lost pitch control off the California coast. The NTSB found the threads on the jackscrew’s nut had worn away because the part hadn’t been lubricated enough. The NTSB’s recommendations that followed focused on how these systems are lubricated and inspected.

The vertical stabiliser, or fin, works like the feathers on an arrow: if the nose swings off to one side, the airflow pushes the tail back into line. The rudder on its back edge swings the nose left or right. Pilots use it to stay straight on the runway, to line up with the centreline in a crosswind, and above all to hold the aircraft straight if an engine fails and the other one tries to swing it round. In normal turns, a system called a yaw damper does most of the small rudder work automatically.

The tail fin and rudder of an Airbus A380 — The fin and rudder of an Airbus A380. The rudder is the hinged rear part of the fin. Photo: Wikimedia Commons (author and licence on the file page).

What Flight 587 changed

Before 2001, many pilots believed that below a certain speed, called the design manoeuvring speed, any control input was safe. Flight 587 showed that full rudder one way and then the other could overload the fin even below that speed. Upset-recovery training was revised to stop teaching heavy rudder use, and guidance now spells out that the protection covers a single full input, not repeated reversals. The rudder is for yaw, used gently. That’s the job, and only that job.

Sources & Further Reading

Common Questions

Frequently Asked Questions

What are the moving parts on a plane’s wing called?

From the outer tip inwards: the aileron on the back edge near the tip, flaps on the back edge closer to the fuselage, slats along the front edge, and spoilers, the panels that pop up from the top surface. Many airliners also have a winglet at the very tip, which doesn’t move.

Does the rudder turn the plane?

Not on its own. An airliner turns by banking with the ailerons (and spoilers), so part of the wing’s lift pulls it round the turn. The rudder keeps the turn tidy and holds the aircraft straight after an engine failure or in a crosswind.

Why do panels pop up on the wing after landing?

Those are ground spoilers, sometimes called lift dumpers. The crew arms them before landing and they deploy automatically when the wheels touch. They kill the wing’s lift, so the aircraft’s full weight presses on the wheels and the brakes work properly.

What do winglets do?

They weaken the swirling vortex that forms at each wingtip, which cuts a type of drag called induced drag. Less drag means less fuel. NASA flight tests of Richard Whitcomb’s winglets on a KC-135 in 1979 and 1980 showed a clear gain in the wing’s lift-to-drag ratio.

What is the tail of a plane called?

The tail (empennage) has two parts. The horizontal stabiliser, with elevators on its back edge, controls pitch: nose up or down. The vertical stabiliser, or fin, with the rudder on its back edge, controls yaw: nose left or right.

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Last reviewed: October 2026. Facts that change, such as fleets, airspace and airline ownership, are re-checked on a schedule. Spotted an error? Email contact@skyplus.news and we’ll fix it. See how we check facts.