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Why do commercial airflights have those letters and numbers? Here’s why!

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Airport codes, numbers, and technical lingo might seem arcane or even random at first glance, but most have surprisingly logical origins. From international abbreviations to behind-the-scenes terms used by airport staff, there’s a whole coded world buzzing around your flight. Let’s unpack 10 of the most widely used ones.

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IATA airport codes are those three-letter codes you see on tickets and baggage tags, like LAX for Los Angeles or JFK for New York. They're set by the International Air Transport Association (the aforementioned IATA).

These codes often reflect the airport’s name or location, but not always. Some are not as obvious, like ORD for Chicago O’Hare, which comes from its previous name: Orchard Field.

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A relative of the IATA airport codes, UN/LOCODEs are five-character codes used in global trade and transport. They combine a two-letter country code with a three-letter location code, like USLAX for Los Angeles in the U.S.

These codes help standardize locations in shipping, logistics, and customs. You might not see them as often as airport codes, but they’re essential behind the scenes in moving goods worldwide.

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Airport terminal and gate codes help guide you through the airport. A sign like T1-G12 means Terminal 1, Gate 12.

Each airport has its own layout, so the letters and numbers can vary. Some use concourses (like B42), while others just number gates.

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Runway designators are those numbers you see at each end of an airport runway, like 09/27. They’re based on compass directions. For example, 09 means 90°, or east, and 27 means 270°, or west.

If there are parallel runways, you’ll see letters too, like L for left or R for right (e.g., 09L/27R).

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Airline and flight number codes help identify specific flights, like AA100 for American Airlines Flight 100. The first part is the airline’s IATA code, followed by a number assigned to the route.

These codes are used in schedules, boarding passes, and announcements.

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A-CDM codes are used at airports to help controllers and pilots work together smoothly using universal directives. They stand for Airport Collaborative Decision Making.

Some examples of these kinds of codes are TOBT (Target Off-Block Time) and TSAT (Target Start-up Approval Time), which help coordinate when planes should push back or start engines.

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METAR and TAF codes use ICAO airport codes to report weather conditions for pilots and flight crews. For example, EGLL is used in METAR reports for London Heathrow.

These reports include info like wind, visibility, and temperature. METARs show current weather, while TAFs give forecasts.

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Baggage tag numbers and codes are the barcodes that are attached to the luggage when it is checked. They usually include the airport's IATA code, like LAX123456, to help route the bag correctly.

These tags let airports and airlines track bags from drop-off to arrival.

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Flight status codes are seen on airport screens, like ON TIME, DELAYED, or BOARDING, to keep passengers updated. They’re simple but super helpful when you’re rushing to your gate.

Other codes can be spotted, like DEP (Departed), ARR (Arrived), ETA (Estimated Time of Arrival), and GATE CLOSED.

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Flight numbers help identify each flight and usually include four or five digits after the airline code. These numbers aren’t random: they often reveal details like the route, destination, or flight type.

For example, Lufthansa uses 400s for North America and 900s for Asia. Some airlines even assign numbers based on the country of origin.

Blame evolution: 10 reasons why cats are (not) the worst pets

Cats often get a reputation for being difficult, distant, or unreliable pets. People who grew up with dogs sometimes describe them as cold, stubborn, or uninterested in pleasing anyone. This list looks at familiar cat behaviors that can feel frustrating at first, especially to new owners. Seen more closely, these same traits help explain why cats fit comfortably into many homes and why millions of people continue to choose them as companions year after year. Continue reading to discover that your cat truly loves you!

Calling a cat by name and getting no response is a common experience. Unlike dogs, cats rarely come running just because they are called. This can feel dismissive, even rude, to owners who expect a pet to respond on cue.

What’s often overlooked is that cats evolved as mostly solitary hunters. They did not develop social behaviors centered on following leaders or responding to group signals. Studies and everyday observation show that cats can recognize their names and the sound of their owner’s voice, but they decide for themselves whether to react or not. For many people, this independence means fewer demands for constant interaction and a pet that is comfortable spending time on its own.

Many cat owners know the sound: a slow tap, a pause, and then a cup or pen sliding off the edge of a table. Cats often push objects while watching closely, as if waiting for the result.

This behavior is tied to curiosity and learning. Cats use their paws to test how objects move, whether they roll, wobble, or fall. This kind of testing is connected to hunting instincts, where judging motion and distance matters. While it can be annoying, it also shows that cats stay mentally engaged with their environment instead of simply reacting to commands or routines.

Some cats appear deeply committed to a favorite chair, window, or room, while paying less attention to following their owners around the house. This can be mistaken for emotional distance.

In reality, cats rely heavily on familiar spaces. Territorial behavior is well documented in feline behavior, and known areas provide safety and predictability. Many cats show affection by choosing to remain near trusted people within these familiar spots. Staying close without constant contact is often how cats express comfort and attachment. It looks like indifference. It usually isn’t.

Cats can learn routines, such as using a litter box or recognizing feeding times, but they rarely perform tricks or tasks simply to please people. Compared to dogs, they are often labeled "untrainable." Domestication helps explain this difference. Cats were domesticated much later than dogs and retained more independent behavior. Dogs were bred over thousands of years for cooperation with humans, while cats largely adapted themselves to human environments. For many owners, this means living with an animal whose behavior feels consistent and self-directed, rather than shaped by constant training.

Adult cats sleep a lot—often 12 to 16 hours a day. This pattern comes from their natural rhythm as predators that conserve energy between short periods of activity. Instead of constant attention-seeking, cats rest when nothing demands their focus. For many households, this makes cats easier to live with, especially for people who value quiet or spend part of the day away from home.

Cats frequently refuse foods that dogs would eat without hesitation. They are obligate carnivores, meaning their bodies are designed to rely on nutrients found primarily in meat. They require specific amino acids that plant-based foods do not provide. Their selectiveness reflects a digestive system shaped by evolution, not stubbornness. Once owners understand this, feeding routines often become simpler and more predictable.

Every new couch seems to be noticed immediately. Scratching furniture is one of the most common complaints about cats: sofas, chairs, and rugs often suffer. Scratching serves several purposes. It helps cats stretch muscles, maintain claw health, and mark territory using scent glands in their paws. While scratching can damage household items, the behavior itself supports physical comfort and well-being. Providing appropriate scratching surfaces allows cats to meet this need without constant correction.

Some cats nip during play or petting, especially when stimulation becomes too intense. It feels personal, but it rarely is. In many cases, cats show subtle warning signs first, such as tail flicking, ear movement, or muscle tension. Overstimulation, particularly around sensitive areas like the tail or lower back, triggers these reactions. Owners who learn to read these signals often find that cats communicate boundaries clearly and consistently.

Cats are often active early in the morning or late at night, which can interrupt your sleep. This crepuscular pattern comes from hunting instincts, as small prey animals are active at those times. Even indoor cats retain this rhythm. While it doesn’t always align with human sleep schedules, it also means cats can go about life without constant attention during the day, when many households are busiest.

Cats may ignore attention for long periods and then suddenly want closeness. This shift can feel confusing or inconsistent. They usually approach people when they feel calm and secure. Affection offered on their terms often feels different—and more noticeable—than affection given on demand. For many owners, these moments feel meaningful precisely because they happen by the cat’s choice rather than by routine or training.