Planeology
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Flight plan · 24 guides

Guides to how flying works

The questions people really ask about planes, answered in plain English and checked against official sources. Grouped the way the app's 15 lesson groups are.

LEG 01

How Flight Works

An airliner in level flight with four arrows: lift pointing up, weight down, thrust forward and drag backward

How Flight Works · 7 min

How Do Planes Fly? Lift, Thrust, Drag and Weight, Explained

A wing bends the air downward and the air pushes back. Everything else about flight follows from that one idea.
An overhead view of an airport with two runways, a taxiway and a curved terminal with airliners parked at its gates

How Flight Works · 8 min

How to Learn About Aviation: A Beginner's Guide for Avgeeks

You don't need a pilot's license to understand how flying works. You need a map of the subject, a few trustworthy sources and a little curiosity every day.
A light airplane pitched nose-high with the smooth airflow breaking into swirls above its wing as arrows show the air approaching from ahead

How Flight Works · 7 min

What Is a Stall in an Aircraft? (It's Not the Engine)

The engine keeps running. What stops working is the smooth flow of air over the wing.
LEG 02

Anatomy of an Airplane

An airliner on final approach with its trailing-edge flaps lowered, and an inset showing the flap hinged down behind the wing section

Anatomy of an Airplane · 7 min

What Are Those Moving Parts on the Wing? Flaps, Slats and Spoilers

A wing built for fast cruising has to land slowly. The moving parts are how it changes shape to do both.
LEG 03

Engines & Propulsion

A cutaway turbojet with a blue arrow entering the compressor, a flame in the combustion chamber, turbine blades behind it and hot exhaust leaving the nozzle

Engines & Propulsion · 7 min

How Do Jet Engines Work? Turbojets, Turbofans and Turboprops

Squeeze air, burn fuel in it, and let the hot gas spin a turbine on its way out. Every jet engine is a variation on that loop.
LEG 04

In the Cockpit

An airliner in level flight with a dashed line through it and a looping arrow circling the airplane, showing it holding a set altitude and heading

In the Cockpit · 7 min

How Does Autopilot Work? Do Pilots Still Fly the Plane?

An autopilot holds whatever it is told to hold. The interesting part is who tells it, and what happens when the wires replace the cables.
LEG 05

Airports & Air Traffic Control

A brown suitcase on a baggage belt with a tag reading GVA above a barcode

Airports & Air Traffic Control · 7 min

Airport Codes Explained: Why Chicago Is ORD and Los Angeles Is LAX

Some codes are the first three letters of the city. The rest are history lessons in disguise.
A yellow flight path climbing from an airport tower, through a dome of approach airspace, into a high en route corridor watched by a radar dish on a hill

Airports & Air Traffic Control · 7 min

How Does Air Traffic Control Work? From the Tower to the Ocean

A relay of controllers hands every flight along like a baton, from the gate to 35,000 feet and back down again.
A compass rose beside a runway seen from above, numbered 36 at one end and 18 at the other

Airports & Air Traffic Control · 8 min

What Do Runway Numbers Mean? Headings, Letters and Stripes Explained

The big painted numbers are compass headings in disguise, and they quietly change as the magnetic pole wanders.
LEG 06

Navigation & Weather

An airliner cruising above mountains while rising currents of sun-warmed air and swirling eddies off the peaks disturb the air below it

Navigation & Weather · 8 min

Is Turbulence Dangerous? What's Happening When the Plane Shakes

Turbulence is uneven air, not a failing airplane. Here is where the bumps come from, how much a wing can take, and what the records actually show.
A four-engine jet in a deep blue sky trailing four white contrails, with a magnified circle showing the trails are made of ice crystals

Navigation & Weather · 7 min

What Are Contrails? Why Planes Leave White Trails

Those white lines are clouds made of ice. Whether they vanish in seconds or spread across the sky depends on the air miles above your head.
Blue dots thinning with height show the air getting less dense, with a small propeller plane low down and an airliner cruising above a dashed line

Navigation & Weather · 8 min

Why Do Planes Fly at 35,000 Feet? Thin Air, Smooth Rides and Saved Fuel

Thin air is cheap air to fly through. Climb high enough and most of the weather, and most of the atmosphere, is beneath you.
An eastbound airliner riding a band of fast wind drawn as streamlines, above a westbound airliner flying into three dark headwind arrows over the ocean

Navigation & Weather · 7 min

Why Is Flying East Faster Than Flying West?

Same airplane, same distance, different time. The difference is a river of fast wind several miles up.
LEG 07

Pioneers of Flight

The 1903 Wright Flyer lifting off its wooden launching rail over the sand at Kitty Hawk, with a pilot lying on the lower wing and a man running alongside under a gray sky

Pioneers of Flight · 7 min

The Wright Brothers' First Flight: 12 Seconds That Changed the World

Four flights on a cold morning at Kitty Hawk, the longest under a minute, and nothing was ever quite the same.
LEG 10

The Jet Age

A sleek jet with circular sound waves bunching together at its nose into one straight front, beside a speed dial with its needle at a red mark

The Jet Age · 8 min

What Is Mach 1? The Speed of Sound and the Sound Barrier

Mach 1 isn't a fixed speed. It is the speed of sound in the air around an aircraft, and that depends on how cold the air is.
A square window cutout with a magnified crack running from a rivet hole, beside an oval window cutout set in a reinforced panel

The Jet Age · 7 min

Why Are Airplane Windows Round? The Comet Story

Square corners concentrate stress. The first jet airliner learned that the hard way, and every window since has carried the lesson.
LEG 11

Airliners & Airlines

Two lineups of three airliners, small, medium and large, face each other across a runway

Airliners & Airlines · 7 min

Boeing vs Airbus: How to Tell a 737 From an A320

Two companies build nearly every jet you will ever board. Their airplanes give themselves away at the nose, the engines and the wingtips, once you know where to look.
Cross-section of the A380's two passenger decks and cargo hold, beside a small side view showing where the slice is taken

Airliners & Airlines · 7 min

The Biggest Planes in the World

Biggest by what? Weight, wingspan and seat count each crown a different giant, and the heaviest of them all no longer exists.
LEG 12

Speed & Altitude Legends

A bar chart comparing the speeds of an airliner, Concorde, the SR-71 and the rocket-powered X-15, whose bar runs far to the right

Speed & Altitude Legends · 7 min

The Fastest Planes Ever Flown: From the X-1 to the X-15

The speed record for a piloted airplane has stood since 1967. Here is who holds it, who came closest, and why the fastest aircraft are all so old.
A retired Concorde on display in a museum hall, with a family and other visitors looking up at it

Speed & Altitude Legends · 7 min

Why Was Concorde Retired, and Is Supersonic Travel Coming Back?

A hundred seats, a ton of fuel per seat and a boom that kept it over the ocean. Concorde's story explains why the next supersonic airliner looks so different.
LEG 13

Military Aviation

A red helicopter with its main rotor disk shaded above it and a small tail rotor, with an inset showing the airfoil cross-section of one blade

Military Aviation · 7 min

How Do Helicopters Fly? Rotors, Torque and the Tail That Fixes It

A helicopter does not need a runway because its wings never stop moving. Everything else follows from that.
Radar beams striking a dark faceted shape and bouncing away at angles instead of back toward the dish, with a faint F-117 behind it

Military Aviation · 6 min

How Does Stealth Technology Work on Aircraft?

Stealth does not make an airplane invisible. It makes the echo so faint, and so late, that the defender runs out of time.
LEG 14

Safety & Lessons Learned

Four slices of Swiss cheese standing in a row, with a red arrow passing through holes in the first two slices and stopping at the third

Safety & Lessons Learned · 8 min

How Safe Is Flying, Really?

The numbers, dated and sourced, and the layered system of defenses that produces them.
Two bright orange flight recorders with white stripes on a bench, one marked with a graph for flight data and the other with a sound wave for cockpit audio

Safety & Lessons Learned · 6 min

Why Are Black Boxes Orange? What Flight Recorders Do

They are bright orange, there are two of them, and they are built to outlast almost anything. Here is what they record and why.