The real delay rate depends on which airline, which airport, and which season you're looking at
There is no single percentage that applies everywhere. The U.S. Department of Transportation tracks on-time performance for major airlines, and the numbers shift month to month. In recent years, roughly 20 to 25 percent of flights arrive more than 15 minutes late—but that figure varies sharply by carrier, airport, and time of year. Some airlines and routes run closer to 15 percent delays; others hit 30 percent or higher during peak travel seasons.
The delay rate also depends on how you define "delayed." The government counts a flight as late if it arrives 15 minutes or more after the scheduled time. Some travelers care about any delay at all; others only worry about missing a connection. Understanding which delays affect you most helps you plan around them.
Key Takeaways
- The U.S. Department of Transportation publishes monthly on-time performance data for each major airline, showing which carriers delay flights most often.
- Delays vary by season, with summer and holiday periods seeing higher rates than winter and spring.
- Certain airports—particularly those in the Northeast and at major hubs—experience more delays than others.
- Weather, air traffic congestion, and mechanical issues are the three largest causes of flight delays.
- A flight is counted as delayed if it arrives 15 minutes or more after the scheduled arrival time.
Which airlines delay most often
The Department of Transportation publishes a monthly report called the Air Travel Consumer Report, which ranks major U.S. airlines by on-time performance. The rankings change from month to month, but a few patterns hold steady. Carriers that operate many regional routes or serve smaller airports tend to have higher delay rates than those focused on major hubs. Budget airlines sometimes show higher delays than full-service carriers, though this varies by month.
You can find the current month's rankings on the DOT website under "Air Travel Consumer Report." The report lists each airline's on-time arrival percentage, the number of flights delayed by more than 15 minutes, and the number cancelled. This is the most reliable source for comparing which airline is most likely to run on time for your specific route.
How season and weather affect delay rates
Delays spike during summer (June through August) and around major holidays. Summer sees the highest passenger volume, which creates bottlenecks at busy airports. Winter weather—snow, ice, and fog—causes delays in northern regions, particularly the Northeast. Spring and fall typically have the lowest delay rates because weather is more stable and passenger loads are lighter.
Weather accounts for roughly 30 to 40 percent of all delays. Thunderstorms, heavy snow, and fog ground flights or slow air traffic. Mechanical delays and air traffic congestion make up most of the remainder. If you fly in July or during Thanksgiving week, expect a higher chance of delay than if you fly in April or September.
Which airports experience the most delays
Large hub airports in the Northeast—Newark, LaGuardia, and Boston—consistently rank among the worst for on-time performance. Chicago O'Hare, Atlanta Hartsfield-Jackson, and Dallas-Fort Worth also see frequent delays because they handle enormous passenger volumes and experience weather disruptions. Smaller regional airports and those in the South and West generally have better on-time records.
Delays at hub airports ripple outward. If your connecting flight departs from a chronically delayed airport, you face a higher risk of missing it, even if your first flight arrives on time. When booking a connection, check the on-time performance of both the departure and arrival airports, not just the airlines.
What causes delays and how long they typically last
The three main causes are weather (about 30 to 40 percent of delays), air traffic congestion (about 20 to 30 percent), and mechanical or crew issues (about 20 to 25 percent). Other causes include security delays, passenger boarding issues, and baggage handling problems. A weather delay might last 30 minutes to several hours depending on the storm. A mechanical delay could be resolved in an hour or stretch into a full cancellation.
Most delays last between 15 and 60 minutes. Delays longer than two hours are less common but do happen, particularly during severe weather or when a mechanical issue requires parts or a crew change. If you have a tight connection, a one-hour delay on your first flight could cause you to miss it.
How to check delay history for your specific route
The DOT Air Travel Consumer Report shows on-time performance by airline and month, but it does not break down individual routes. For route-specific history, use the Bureau of Transportation Statistics website, which lets you search historical delay data by origin airport, destination airport, airline, and date range. FlightAware and similar flight-tracking sites also show historical delays for specific routes, though they are less official than government data.
If you are booking a flight months in advance, historical data from the same month in previous years gives you a sense of what to expect. A flight from New York to Miami in July will likely have a higher delay rate than the same route in October. Checking the specific airport pair and season helps you plan more realistically than relying on national averages.
How delays affect your plans and what you can do about them
A 15-minute delay usually does not affect your day, but it can cost you a connection. If you have a tight layover—less than 90 minutes on a domestic flight—a delay on your first leg puts you at real risk of missing your second flight. When booking, check the on-time performance of both legs and consider building in extra time if either airport or airline has a weak record.
If your flight is delayed, you are may have access to to a rebooking on the next available flight at no extra cost. Airlines are not required to pay compensation for delays (unlike in Europe), but they must get you to your destination. Arriving late is frustrating, but it is not the same as being stranded. Knowing the delay history of your route helps you decide whether to book a tight connection or pay for a longer layover.
Frequently Asked Questions
What percentage of flights are delayed by more than an hour?
Roughly 5 to 10 percent of flights are delayed by more than 60 minutes, depending on the airline and season. This varies month to month. Summer and holiday travel see higher rates. You can check the specific airline and month in the DOT Air Travel Consumer Report.
Do budget airlines have worse on-time records than major carriers?
Not always. Some budget airlines run on time better than full-service carriers in certain months. The DOT report ranks all major airlines monthly, so you can compare them directly. Performance varies by month and route, so check the current report for the airline and month you are flying.
Is there a best time of day to fly to avoid delays?
Early morning flights (before 9 a.m.) tend to have fewer delays because there is less air traffic congestion and fewer cascading delays from earlier flights. Afternoon and evening flights are more likely to be delayed because problems from earlier in the day compound. However, weather and mechanical issues can strike any time.
Can I get money back if my flight is delayed?
U.S. airlines are not required to pay compensation for delays. They must rebook you on the next available flight at no cost, but they do not owe you money unless the delay was caused by something within their control (like a crew scheduling error). European airlines have different rules and may owe compensation.
How do I learn about my specific flight route is usually delayed?
Use the Bureau of Transportation Statistics website to search historical delay data by origin airport, destination airport, and airline. You can also check FlightAware for historical delay patterns on your route. The DOT Air Travel Consumer Report shows delays by airline and month, which gives you a general sense of risk.