Flight delays are common, with almost 20% of flights being delayed for at least 15 minutes, and they are inevitably frustrating for passengers.

But why do flights even get delayed in the first place?

Most flights get delayed because of bad weather, a technical issue, because the plane is waiting to receive cargo, or because the pilot hasn’t been given security clearance yet.

If your flight is delayed or canceled, depending on what country you are flying from, you may be entitled to compensation.

If your flight gets canceled, most airlines will schedule you onto the next available flight to your intended destination without additional charges.

Even if your flight gets delayed, you should still get to the airport on time to check in.

5 Reasons Why Flights Get Delayed

These are the 5 most common reasons for flight delays:

1. Weather conditions

Bad weather is one of the most common reasons for flights delays.

Bad weather, such as tropical storms, tornadoes, and severe rain, prevent planes from safely taking off.

Generally, airlines only delay flights during extreme weather conditions.

Every airport has its own standard for bad weather, but in the US, airports mostly follow national regulatory bodies like the Federal Aviation Authority (FAA). 

2. Knock-on Effect Due to Delayed Aircraft

A knock-on or rotational delay is when a flight is delayed because the plane arrived late.

Airlines commonly assign a plane to multiple consecutive flights, so it’s pretty much inevitable for your flight to be delayed if the plane’s previous flight was also delayed. 

3. Staff Strike

Like with other industries, airline staff can cause delays by going on strike for labor negotiations.

Depending on the number of staff on strike and their duration of being on strike, the delay can range from a few hours to multiple days.

For example, British Airways pilots went on a 48-hour strike in September 2019, with their strike delaying multiple flights by many hours. 

4. Mechanical Issue(s) With the Aircraft

Airlines have to ensure their planes maintain strict maintenance requirements.

So, it’s common for flight delays to be caused by technical issues, even minor ones like: 

  • Aircraft parking issues
  • Fuel contamination 
  • Contamination of the water draining system 
  • Contamination of the air conditioning system

5. Bird Strikes

A bird strike is when an aircraft collides with a bird.

Bird strikes are relatively common, with an average of 13,000 bird strikes in the US alone.

Bird strikes predominantly happen during either takeoff or landing since the plane is at low altitudes, and are considered a security threat, although they don’t cause much damage.

The damage from a bird strike depends on the plane’s size, with planes with larger engines generally experiencing the most damage.

Bird strikes can cause partial or complete loss of control because of engine ingestion. 

Why Flights Are Sometimes Delayed For a Very Short Time

Short flight delays, between 10 and 60 minutes, are often caused by these 5 problems. 

1. Waiting for Cargo

Commercial airlines carry cargo in addition to passengers and their luggage.

Sometimes delivery of this cargo gets delayed, causing a short flight delay. 

2. Waiting for Connecting Bags

Passengers with one or more connecting flights travel with checked-in luggage that sometimes takes time to transfer to the next flight. 

3. Complying with Weight Restrictions

For safety reasons, airplanes aren’t permitted to fly if their weight exceeds a maximum takeoff weight (MTOW).

Airlines often delay flights to ensure their aircraft doesn’t weigh more than its MTOW. 

4. Getting Security Clearance

Airplanes must receive security clearance before taking off.

Sometimes, it takes extra time to receive security clearance, which can cause flight delays of up to 10 to 20 minutes. 

Related: Why Do Airlines Change Flight Times?

If Your Flight is Delayed, Still Go to the Airport

You should still go to the airport even if your flight is delayed.

Depending on the cause of the delay, the flight could receive clearance to fly at any moment. Most flight delays are unlikely to be longer than an hour.

You’re also not allowed to check in later than your original check-in time.

A Delayed Flight Might Mean Compensation

Every country has different legal requirements for when flights are delayed or canceled. 


Airlines are not legally required to compensate passengers if their flights are delayed or canceled.

The US only requires compensation for passengers who are ‘bumped’ from an oversold flight. 


Canadian law requires airlines to compensate passengers if their flight is delayed for more than 3 hours due to a non-safety issue within the carrier’s control. 


The EU requires airlines to compensate travelers if passengers arrive at their final destination with a delay of more than 3 hours unless the delay was due to “extraordinary circumstances”, like labor airline strikes or technical issues. 


British law requires airlines to compensate passengers if the flight arrives at its destination more than 3 hours late, depending on the cause of the delay.

British law normally doesn’t require airlines to compensate passengers if the delay was caused by factors outside their control, like bad weather. 

Rest of the World

Every country has its own laws regarding whether airlines owe compensation for flight delays.

Generally, most of the world has relaxed laws around whether airlines owe compensation. 

Why Flights Are Sometimes Canceled

Flights are canceled for multiple reasons, including bad weather, safety reasons, or labor shortages.

Bad weather is generally the most common reason for flight cancellations since bad weather, like thunderstorms, tropical storms, and severe rain, prevents safe takeoff. 

Safety reasons for canceling flights include mechanical issues in the plane, the plane exceeding its maximum takeoff weight, or other safety concerns. Even technical issues like computer outages can cancel a flight. 

Lastly, airlines may cancel a flight if they don’t have enough flight crew.

A labor shortage could be caused by too many sick crew members, scheduling errors, or labor strikes.

If your flight is canceled, most airlines will reschedule you for the next available flight to your destination without additional cost. 

An Airline May Pay for Your Accommodation and Travel Costs

Whether an airline pays for your accommodation and travel costs because of a flight cancellation depends on the country you are flying from.

Generally, it’s common for airlines to provide passengers with hotel vouchers and to pay for their meals and travel expenses if a flight is canceled because of something within their control. 

In conclusion:

  • Flights get delayed because of bad weather, labor shortages, technical issues, or waiting to receive cargo or security clearance.
  • Almost 20% of flights are delayed by at least 15 minutes, but it’s not common for flights to be delayed for longer.
  • Every country has its own laws regarding whether airlines compensate passengers for delaying or canceling their flights.
  • You should still arrive at the airport in time even if your flight gets delayed because it could take off at any time.
  • You’re also not allowed to check in late, even if your flight is delayed for multiple hours.

Ella Dunham, a Freelance Travel Journalist and Marketing Manager, boasts an impressive career spanning eight years in the travel and tourism sectors.

Honored as one of "30 Under 30" by TTG Media (the world’s very first weekly travel trade newspaper), a "Tour Operator Travel Guru" and "Legend Award" winner, Ella is also a Fellow of the Institute of Travel, a Member of the Association of Women Travel Executives, has completed over 250 travel modules, and hosts travel-focused segments on national radio shows where she provides insights on travel regulations and destinations.

Ella has visited over 40 countries (with 10 more planned this year).