This Is What Secretly Happens When Your Flight Is Delayed

You arrive at the airport early, make it through security, grab a bite, and settle in for a short wait at your gate—then BOOM!—your flight is suddenly delayed three hours, and now you're stuck surrounded by 150 other disgruntled passengers. While a plane delay is never an ideal situation, there's usually a pretty solid reason behind it, especially when it comes to the safety of the crew and people on board. So, if you're wondering what's actually happening behind the scenes, read on, dear frequent flyer.

Fact: About 40 percent of all flight delays are due to late arrivals. Planes are always in motion, hopping from one airport to the next. Although there's a little buffer time between a plane's arrival and its next departure, if your plane is delayed for any reason on its journey to the airport, your flight might also be bumped back in a chain reaction that could impact flights all day long. Keep an eye on your plane's inbound flight either through your airline's app (usually there's a button saying "Where is my plane now?" or some similar verbiage) or through a third-party flight tracking site like Flightradar 24 or Flight Aware.

There are general weather delays, and then there are extreme weather delays. The former includes thunderstorms, fog, and high winds while the latter includes tornados, hurricanes, and blizzards. That bad weather could be either at your departure airport, your arrival airport, or anywhere along your route. The good news? Only about five percent of flight delays are due to extreme weather.

Rush hour isn't just on the streets, it's on the tarmac, too. Air Traffic Control (ATC) has to carefully monitor and guide all inbound and outbound planes on the ground and the air, so if controllers are a little bogged down, they could delay your flight to clear up some congestion.

Note: Anything related to the general state of airports and ATC that's not tied specifically to the airline—like runway traffic and airport operations (see below)—fall under the category of National Aviation Systems (NAS) delays, which account for roughly 25 percent of all flight delays.

Airports require quite a bit of maintenance in order to keep things running smoothly and safely. For instance, if there's a bit of snow on the ground, the airport may need to pause take-offs and landings in order to plow the runways and taxiways. When this happens, flights often get delayed. There's also the issue of strikes by the ground crew, particularly in Europe. If there are fewer ground staff available, operations might lag, and flights might be delayed.

Any delays that are due to the airline's operations are called carrier delays, and they comprise some 30 percent of all delays. One such example is mechanical issues. Planes undergo thorough inspections between flights. If everything checks out, then great! You'll be off in no time. But if something is wrong, whether that's a big issue like a problem with the plane's landing gear or one as simple as an overhead bin not locking properly, airline staff will need time to fix it.ae0fcc31ae342fd3a1346ebb1f342fcb

Between flights, the cabin needs to be cleaned, the plane needs to be refueled, and supplies like food and toilet paper need to be restocked. If any of the teams responsible for those duties are running behind schedule, the flight might be delayed until the tasks are complete.

All sorts of things can go wrong with the crew, from a crew that's delayed on an inbound flight to a crew timing out. Pilots and flight attendants have limits to how many hours they can work in a row, so as to reduce the risk of human error on a flight, sometimes they might time out in the middle of a flight if there are delays, which would necessitate a replacement crew to take over.

It doesn't happen too often, but sometimes there's a snafu in the baggage loading process, and the plane may be held to make sure everyone's luggage gets loaded into the hold.

Though only 0.1 percent of delays are due to security issues, they do happen occasionally. A security delay is typically due to a terminal being evacuated or a security breach when boarding. The next time you book a flight, watch out for the 13 Worst Airports to Fly Into, According to Pilots.